HPB

Question 1

Aberrant biliary anatomy

Answer 1

• aberrant hepatic duct = defined as a duct draining a normal portion of the liver that joins the biliary tree outside of the liver
• normally the RHD is divided into a right anterior (medial) and a right posterior (lateral) branch which join to form a short right bile duct which joins with the left to form a CHD
• variations in 30-40%
• most common variations relate to right posterior sectoral duct which may drain into:
  
  • left hepatic duct - 15%
  • directly into CBD - 10%
  • tirfurcation with R ASD and LHD 11%
• anatomy of left hepatic duct more constant

Question 2

Aberrant hepatic arterial anatomy

Answer 2

• either of the right or left hepatic arteries may be replaced or accessory
• 10-15% right hepatic artery is replaced or has an accessory coming from the SMA
  
  • artery typically runs from right to left behind the CHD and PV
  • may be at risk during pancreatectomy
  • typically, the RHA gives off the cystic artery & if the RHA is aberrant or replaced it tends to give off a cystic artery that is more lateral to the cystic duct (ie in free edge & may be mistaken for CD)
• 6-10% left hepatic artery is replaced or has an accessory from the left gastric artery where it runs in the gastrohepatic ligament
  
  • may be at risk in oesophagogastric surgery and usu divided in oesophagectomy in order to create an anastomosis within the chest

Question 3

Aberrant portal vein anatomy

Answer 3

variations relatively uncommon

most common = trifurcation - division into left, right anteiror and right posterior branches

other variations include right anterior or posterior arising from portal vein early, or off the left portal vein

Question 4

Aetiology/Risk factors for HCC

Answer 4

• cirrhosis
  
  • and once present male, age, stage of cirhrosis, diabetes
  • highest risk for chronic viral hepatitis
• hep B
  
  • accounts for >50% cases worldwide, >70% in NZ
  • co-factors that increase risk: Asian, male, >40yrs, concurrent HCV or HDV, aflatoxin
  • HBV-DNA sequences integrate into genome of malignant hepatocytes & act as oncogene for HCC development
• hep C
  
  • co-factors male, >44yrs, diabetes, ETOH, HBV
  • mechanism unclear but great majority have cirrhosis suggesting its crucial for development of HCC
• HIV
  
  • mainly bc of higher prevalence of assoc risk factors (HCV/HBV, ETOH, NASH, diabetes)
  • HIV pts w HBV or HCV have faster progression
• alcohol
  
  • bc increases cirrhosis risk
• NAFLD
  
  • associated w metabolic syndrome
• hereditary haemochromatosis
• aflatoxin
  
  • toxin ingested in food as a result of contamination of imperfectly stored staple crops by Aspergillus flavus
  • some think independent risk factor; others co-carcinogen w HBV
• adenoma, contraceptives & androgens
  
  • HCAs have risk of malignant transforation & hepatocyte dysplasia
• metabolic liver diseases
  
  • eg alpha-1-antitrypsin deficiency, Wilson disease
• cirrhosis of other aetiologies that rarely cause HCC: PBC, secondary biliary cirrhosis, autoimmune hepatitis

Question 5

Amoebic liver abscess

Answer 5

• Definition: liver abscess due to infection w Enamoeba histolytica (a protozoan)
• Incidence
  
  • account for 10% liver abscesses
  • predominantly found in areas where E. histolytica endemic eg Mexico, India, Africa, parts of Central/South America
  • hispanic males 20-40yrs, increased risk w poverty/cramped living
  • increased incidence w immunosuppression
• Aetiology/Path
  
  • only 10% of those w antibodies get sx, mainly amoebic colitis; liver abscesses found in 1% of clinically infected
  • Exists as trophozoite (can’t survive ext environment nor gastric acid) or cyst (can survive in water, soils & food)
  • ingestion of cyst via faecal-oral spread = cause of amebiasis
  • humans = principal host & main source of infection is human contact w cyst-passing carrier; also contaminated water & veges
  • once ingested, cysts aren’t degraded in stomach & pass to intestine - trophozoite released here & passed onto colon where it invades mucosa resulting in disease
  • trophozoites reach liver through portal venous system; no evidence for them passing through lymphatics (can also travel to distant organs eg lungs/brain)
  • abscess formed by progressive localised hepatic necrosis –> produces cavity containing acellular proteinaceous debris surrounded by rim of invasive amebic trophozoites
  • cavity = full o flbood & liquefied liver tissue (anchovy sauce - thick, reddish brown & yellow, odourless unless seocndary bacterial infection)
  • progressive hepatic necrosis continues til Glisson capsule reached bc capsule resistant to hydrolysis by amoebae; thus amoebic abscesses tend to abut liver capsule
  • amoebae can be found at edge of lesion but rarely within abscess cavity itself
  • chronic abscess can develop fibrous capsule
  • can rupture into subphrenic space, pleura, lung or pericardium (rare)
• Clinical
  
  • usu more unwell than pyogenic abscess - high fever etc
  • 2 types of presentation; acute (sx <10days) more dramatic & >50% have multiple lesions; chronic (sx >2wks) less dramatic & >80% have single right sided lesion
• Investigations
  
  • serology: serum antibodies to Entamoeba species (present in 90-95% of pts)
    
    • false -ves may be obtained early in infection but repeated tests usu come back positive
    • enzyme immunoassay sens of 99% & spec 90%
  • stool for amoeba: smear for trophozoites
  • USS& CT both sensitive; can be difficult to differentiate from pyogenic but epidemiologic & clinical info & +ve amoebic titres may suggest diagnosis
  • if work-up not definitive, can either do therapeutic trial of antiamoebic drugs & if rapid improvement this supports dx; or diagnostic aspiration (pyogenic abscess has bacteria & leukocytes; amebic abscess anchovy sauce & usu neg cultures w no leukocytes)
• Mx
  
  • metronidazole 10days
  • aspiration rarely necessary
  • also treat to eliminate intestinal colonisation by E histolytica/carrier state - luminal agents such as iodoquinol

Question 6

Classification for gallbladder polyps

Answer 6

• Benign
  
  • Non-neoplastic: cholesterol polyps (80%), adenomyomas (25%), inflammatory polyps (10%)
  • Neoplastic: adenomas (4%), other (leiomyomas, fibromas, lipomas etc)
• Malignant
  
  • Adenocarcinoma (80%) – much more common than GB adenomas
  • Miscellaneous (20%) – mucinous cystadenomas, SCC, adenocanthomas

Question 7

Clinical prsentation of Hydatid Cyst

Answer 7

• grow slowly, may be asymptomatic for years
• pain/discomfort in upper abdo, loss of appetite, wt loss, hepatomegaly
• acute pain - infection or rupture of cyst
• intra-peritoneal rupture –> anaphylaxis (antigenic cyst fluid released itno peritoneum & circulation)
• rupture into biliary tree w secondary cholangitis/jaundice/acute pancreatitis
• biliary obstruction/cholangitis by daughter cysts/extrinsic compression
• secondary infection of cyst/intracystic/subphrenic abscecss formation
• pressure on hepatic veins –> Budd Chiari syndrome
• bronchobiliary fistula
• later in infection can metastasise to lung, brain, bones, and local extension of lesion (in abdomen retroperitoneum or diaphragm)

Question 8

Criteria for transplant for liver mets

Answer 8

Need to check

Mazzaferro Milan criteria

• confirmed histo dx w primary drained by portal system
• metastatic diffusion to liver parenchyma of ≤50%
• stable diseasee
• age ≤55yrs
• Australian additions: complete resection of primary, no extrahepatic disease

Question 9

Definition of resectable CRLM

Answer 9

• Tumours that can be resected completely (R0)
  
  • resection margin width doesn’t determine long-term survival - just need R0
  • most would require no radiological evidence of involvement of hepatic artery, major bile ducts, main portal vein, coeliac/para-aortic lymph nodes
• Leaving an adequate FLR
  
  • normal underlying liver: ≥20% FLR
  • steatosis or steatohepatitis or chemo: ≥30% FLR
  • underlying cirrhosis (CPA): ≥40% FLR
  • pts who don’t meet FLR requirements may benefit from additional preop procedures to induce hypertrophy of FLR eg PVE or ALPPS
• Extrahepatic sites of the disease are controllable
  
  • ie amenable to surgical resection or long-term oncological control w adjuvant chemo
  • if limited number of lung lesions also present, liver resection usu done first
• Primary tumour can be resected for cure

5 preop factors most influential on outcome = size >5cm, disease-free interval <1yr/synchronous presentation, >1 tumour, LN positive preimary, CEA >200

Question 10

Describe the anatomical classification of the liver segments

Answer 10

The International HPB Association classification divides the liver into 8 functionally independent segments. This is based on both portal supply and (hepatic) venous drainage.

The watersheds of the hepatic artery, biliary system, and portal vein are the same except for the second order division of these structures on the left side; the hepatic artery/biliary watersheds divide the left side of the liver through the umbilical fissure. The portal watersheds are through the plane between segments II and III.

Question 11

Describe the approach to localizing a PNET

Answer 11

• Most non-functioning tumours (85% of PNETs) are seen on CT with arterial and PV phasing.
• Features on CT suggestive of PNETs include hyperdense, hypervascular lesions within the pancreas
• Gastrinomas are usually within the gastrinoma triangle
• High resolution CT and fat-suppressed MRI are equivalent in terms of sensitivity
• EUS improves sensitvity but is operator-dependent
• Somatostatin-receptor-scintigraphy (radio-labelled Somatostatin isotope) is useful for localizing PNETs with the exception of Insulinomas
• FDG-PET is less useful but DOTATATE-PET is relatively sensitive
• Invasive arterial calcium (Insulinomas) and secretin (gastrinomas) stimulation with hepatic/portal venous sampling are only used when all other measures have failed.

Question 12

Describe the classification of bile duct injuries

Answer 12

Strasberg classification (modified from Bismuth)

A = bile leak from cystic duct stump or minor biliary radical in GB fossa

B = occlusion of part of biliary tree, usually aberrant RHD

C = transection but not occlusion of part of biliary tree, usually aberrant RHD

D = bile leak from main bile duct w/o major tissue loss (/lateral injury to biliary tree)

E1 = transection/stricture of main duct >2cm from confluence

E2 = transection/stricture of main duct <2cm from confluence

E3 = transection/stricture at confluence with R and L ducts in continuity

E4 = transection/stricture at confluence with separation of R and L ducts

E5 = combined injury to main duct and RPSD (involve aberrant RHD anatomy)

Question 13

Describe the classification of biliary SOD

Answer 13

Milwaukee (or Hogan-Geenan) classification

• Type I: biliary type pain + abnormal LFTs + dilated CBD
  
  • If delayed drainage at ERCP à sphincterotomy (generally considered to have sphincter stenosis)
• Type II: biliary type pain and abnormal LFTs OR dilated CBD
  
  • Do sphincter manometry à sphincterotomy if abnormal
• Type III: pain only without abnormal LFTs or dilated CBD
  
  • Unlikely to benefit from sphincterotomy

Question 14

Describe the classification of cholangiocarcinoma

Answer 14

• Intrahepatic
• Hilar/perihilar – extends from distal to cystic duct up to and including confluence of right and left bile ducts; further classified by Bismuth-Corlette classification

Type I – involves CHD below biliary confluence

Type II – involves biliary confluence

Type IIIa - involves biliary confluence extending into RHD

Type IIIb – involves biliary confluence extending into LHD

Type IV – involves confluence & extends into both L&RHDs

• Distal extrahepatic – excludes GB & ampulla of Vater

Question 15

Describe the classification of choledochal cysts and their treatment.

Answer 15

Todani classification

• Type I (50%) = fusiform dilatation of extrahepatic bile duct
  
  • cyst resection, cholecystectomy, REYHJ
• Type II (2%) = saccular diverticulum of extrahepatic bile duct
  
  • cyst resection & if APBJ, REYHJ
• Type III = bile duct dilatation within duodenal wall (choledochocoele)
  
  • type IIIA: BD & PD enter cyst, which then drains into duo at a separate orifice (usu present as cystic bulges of the intra-ampullary CBD)
    
    • often amenable to sphincterotomy & bc malignancy rarely been reported should do endosocpic biopsies of cyst epipthelium to determine what the cyst is lined with; biliary mucosa increased risk cf duodenal mucosa); can also do endoscopic snare resection of these
  • type IIIB: a diverticulum of the intraduodenal CBD or intra-ampullary common duct channel; typically present as a penduous fluid-filled mass wtihin duo lumen, distal to and arising from major papilla
    
    • can be resected surgically or endoscopically
  • ?? or Whipple’s now recommended
• Type IV = multiple cysts with involvement of both extrahepatic and intrahepatic ducts (IVa) or extrahepatic only (IVb) – second most common
  
  • IVb - REYHJ
  • IVa - if only one lobe can be treated w partial hepatectomy & recon though controversial if liver resection adds benefit
• Type V = multiple cysts involving intrahepatic ducts only / Caroli’s disease
  
  • lobectomy if confined to one lobe or transplant if diffuse disease

?Treat complications first. Then excise affected disease removing all cyst epithelium and therefore malignant potential. Cholecystectomy and REY hepatico-jejunostomy.

• Complications: cholangitis, primary duct stones (both choledocholithiasis and cystolithiasis), hepatolithiasis, secondary biliary cirrhosis due to prolonged biliary obstruction & recurrent cholangitis, CA (10-30%), intraperitoneal cyst rupture, acute and chronic pancreatitis, bleeding due to erosion of cyst into adjacent vessels or as a result of portal hypertension, often presenting as GI haemorrhage due to haemobilia, GOO from obstruction of duo lumen
• Pathogenesis of malignancy = field change - entire biliary tree at risk, even nondilated portions & complete excision of a benign choledochal cyst doesn’t eliminate risk of subsequent cholangiocarcinoma development

Question 16

Describe the classification of Cirrhosis

Answer 16

The Child-Pugh classification has been used to assess mortality risk in cirrhotic patients undergoing non-shunt surgical procedures:

CP-A=10%, CP-B=30%, CP-C=82% mortality in abdominal surgeries.

CP-A=85%, CP-B=57%, CP-C=35% 2 year survival.

The MELD score is an logarithmic calculation using bilirubin, creatinine and INR that provides a score of between 6-40. There is a modified MELD score that adds in Na.

Question 17

Describe the classification of Mirizzi’s syndrome

Answer 17

Describe classification of Mirizzi syndrome

Mirizzi syndrome = CHD obstruction caused by a gallstone impacted in the cystic duct or Hartmann’s pouch

Type I (11%) = no fistula (type IA = cystic duct present; type IB = cystic duct obliterated)

Type II (41%) = fistula involving <1/3 CBD width

Type III (44%) = fistula involving 1/3-2/3 CBD width

Type IV (1%) = fistula involving >2/3 CBD width / destruction of wall of CBD

Primary surgical management preferred but key concept is that there’s a high probability that the hepatocystic triangle has been obliterated due to fibrosis so must be aware that pursuing a critical view of safety and complete cholecystectomy may be dangerous & lead to a bile duct injury.

• Type I can attempt lap chole but low threshold for subtotal or conversion
• Types II-IV generally require roux-en-Y hepaticojejunostomy; for type II primary closure with T tube insertion described but higher leak rates and morbidity.

OR ERCP + stent as temporizing measure to recover from cholangitis

Question 18

Describe the classification of peri-hilar cholangiocarcinoma

Answer 18

The Bismuth-Corlette classification.

This is anatomic and widely used but does not take into account variables such as tumour extent, lobar atrophy, and vascular involvement, which have significant treatment implications.

Question 19

Describe the classification of post-ERCP perforation (0.1 - 1.8%)

Answer 19

• Howard et al classification:
  
  • Group I - Guidewire perforations
  • Group II - Periampullary lesions
  • Group III - Duodenal perforations remote from the papilla
  • (Group I are likely to heal spontaneously, whereas Group III are likely to need surgery.)
• Sapfer et al: (descending order of severity)
  
  • Type I: lateral or medial wall duodenal perforation
  • Type II: peri-Vaterian injuries
  • Type III: distal bile duct injuries related to wire/basket instrumentation
  • (Type IV: retroperitoneal air alone - not necessarily even a true ‘injury’)
    
    • nb post sphincterotomy retroperitoneal air (13-29%) is a common finding & unhelpful for identifying pts who require intervention)
• duodenal perforations tend to be large, remote from the ampulla, caused by the scope
• periampullary perforations occur mainly due to sphincterotomy
• guidewire/basket injuries tend to be small & will usu seal spontaneously

Question 20

Describe the classification of “Sphincter of Oddi Dysfunction”

Answer 20

Milwaukee (or Hogan-Geenen) Classification:

Delayed drainage is assessed at time of ERCP. In patients with Types I or II, biliary manometry may be considered if there is no evidence of delayed drainage.

Note; PEP rates are higher than the general populaton in these patients.

Question 21

Describe the diagnostic criteria for cholangitis

Answer 21

The Tokyo guidelines, which essentially objectify Charcot’s triad, are very sensitive but specificity has not been assessed in the literature.

Question 22

Describe the distribution of cholangiocarcinoma in the biliary tree

Answer 22

Intrahepatic 10%

Perihilar 65%

Distal 25%

Question 23

Describe the features you look for to determine an adequate assessment in IOC

Answer 23

• visualization of entire CBD & CHD
• tapering of CBD
• evidence of free flow of contrast into duo
• visualization of bile duct ‘trifurcation’
• identification of cystic duct
• no obstructing objects & not projected over spinal column

Question 24

Describe the Fukuoka Guidelines

Answer 24

Guidelines for managment of pancreatic IPMNs and MCNs:

1. All surgically fit patients with MCN, MD-IPMN, and Mixed-IPMN should be offered surgery
2. All surgically fit patients with BD-IPMN with High-Risk Stigmata of Malignany should be offered surgery
3. Patients with BD-IPMN with “Worrisome Features” should undergo EUS
4. Patients with BD-IPMN without “Worrisome Features” or in whom EUS is inconclusive can be surveilled
5. Patients with BD-IPMN >3cm who are young and fit should be strongly considered for surgery.

Question 25

Describe the pathogenesis of recurrent pyogenic cholangitis

Answer 25

• Recurrent pyogenic cholangitis is characterized by recurrent cholangitis caused by bile stasis and stone formation proximal to biliary strictures.
• The pathogenesis of the stone formation and biliary abnormalities is incompletely understood. Stone formation occurs de novo within the intrahepatic bile ducts in contrast with the more common pattern of stone formation within the gallbladder seen in patients with more common forms of gallstone-related disease.
• Transient portal bacteremia is thought to introduce bacteria into the biliary ducts, initiating a cycle of infection and secondary stone formation which leads to further obstruction and infection. Common organisms cultured from bile include E. coli, Klebsiella, Pseudomonas, and Proteus species and, less frequently, anaerobes, although the culture of multiple organisms is common.

Question 26

Describe the pathophysiology of gallstone formation

Answer 26

• Gallstones form due to an imbalance of 3 key products in the bile; bile salts, lecithin, and cholesterol.
• Cholesterol stones form due to a relative supersaturation of cholesterol in the bile, pigment stones form when there is decreased secretion of biliary acids and an increased secretion of unconjugated bilirubin into the bile.
• Stasis and infection also play an important role in the formation of stones.
• The formation of stones falls into three phases; supersaturation, nucleation, and stone growth; the imbalanced mixture generates a precipitant which forms a nidus for further stone formation and crystallisation
• Once formed the stones persist and enlarge or consolidate over time.

Question 27

Describe the staging of intrahepatic cholangiocarcinoma

Answer 27

Traditionally the same as HCC

Question 28

Describe the typical histology seen in Lynch Syndrome Colorectal Cancer

Answer 28

(LaMPS)

• Lymphoid aggregates
• Mucinous pattern
• Poorly differentiated
• Signet ring differentiation

Question 29

Describe TNM staging for HCC

Answer 29

Main issues are size (2cm) and presence of vascular invasion.

Question 30

Diagnosis/Investigations for Hydatid disease

Answer 30

• often causes abnormal LFTs, eosinophilia
• echinococcus serology
  
  • initially use indirect haemoglutination antibody
  • IgG ELISA test for IgG antibodies to hydatid = gold standard
  • neg serology doesn’t r/o echinococcus as high false neg rate in uncomplicated disease; more likely to be neg in non-liver disease, calcified cysts or non-viable cysts (less immunoreactivity)
• Ultrasound - WHO classificatoin
  
  • CL (cystic lesion)
    
    • unilocular, uniformly anechoic cystic lesion w no internal echoes or septations; usu round but may be oval. Can’t diagnose on USS alone; if caused by cystic echinococcus is at early stage of development & usu not fertile
  • CE1 (cystic echinocuccus 1) - active stage
    
    • unilocular, simple round/oval cyst w double-layered wall (representing pericyst & laminated cyst membrane), and uniform anechoic content. Snow-flake sign = fine internal echoes due to shifting of brood capsules called hydatid sand
  • CE2 (cystic echinococcus 2) - active stage
    
    • multivesicular, multiseptated cysts; cyst wall usu visible & lesions round or oval. Presence of daughter cysts indicated by rosette-like honeycomb-like structures (collection w a split wall/internal septations & septa, representative of walls of daughter cysts within hydatid cyst itself)
  • CE3 - transitional stage
    
    • unilocular cyst which may contian daughter cysts; anechoic content w detachment of laminated membrane from cyst wall may be visible as floating membrane or ‘water-lily sign’. Cyst form may be less round bc of decreased intracystic pressure. Cyst may degenerate further or may give rise to daughter cells
      
      • CE3a = daughter cysts have detached - ‘water lily sign’
      • CE3b = daughter cysts sitting within solid matrix
  • CE4 - inactive/degenerative cyst
    
    • cyst characterised by a thick calcified wall that is arch shaped, producing a cone-shaped shadow. Degree of calcificatoin varies from partial to complete. Usu not fertile. Defintiive dx can’t be made by US alone
• CT & MRI - may show findings similar to above; may also demonstrate external rupture of cyst or wall thickening suggestive of infection
• MRI superior for demonstrating cyst wall defects, biliary communication & neural involvement

Question 31

Discuss focal nodular hyperplasia

Answer 31

• benign epithelial tumour - no malignant potential
• second commonest benign solid liver tumour after haemangioma
• F>>>M (no relation to OCP), 20-40yrs (slightly older than HCA)
• Path
  
  • hyperplastic hepatocellular nodules developing in a noncirrhotic liver
  • solitary in 80%
  • peripheral location usu
  • macro: well-circumscribed but not encapsulated, lobular firm tan/yellow-brown mass, with central fibrous scar w radiating septa
  • micro: cords of benign-appearing hepatocytes divided by multiple fibrous septa originating from central scar. Central scar often contains a large artery that branches into multiple smaller arteries in spoke wheel pattern.
• most asymptomatic; rupture, bleeding, infarction exceedingly rare
• imaging
  
  • USS not imaging of choice - iso-echoic, central scar, only subtle difference in echogenicity between FNH & surrounding liver
  • CT & T1 MRI (MRI preferred)
    
    • non-contrast: homogeneous, hypo or isodense cf normal liver (central scar hypodense cf surrounding liver parenchyma)
    • arterial phase: strongly enhancing w central scar remaining non-enhanced
    • venous: isodense again
    • delayed: hyperattenuation of central scar septae often seen
  • T2 MRI: isointense/mildly hyperintense w hyperintense central scar (central scar high attenuation on T2 whereas low in fibrolamellar HCC)
  • when no central scar seen, difficult to differentiate from HCA or malignant mass espec fibrolamellar HCC
• routine biopsy not required; only if dx doubt - some risk of seeding if malignant; alternative interval imaging
• leave alone if dx certain and asymptomatic; no indication to stop OCs
• 50% spontaneously reduce in size

Question 32

Discuss hepatic adenoma

Answer 32

• relatively rare monoclonal proliferation of hepatocytes in context of a normal liver
• F>>M, age 20-40
• associated with steroid hormone use, COC, pregnancy, obesity, T2DM, iron overload
• HCAs in men generally smaller but higher risk of developing into malignancy
• Molecular classification - Bordeaux classification
  
  • HNF1-alpha germline-mutated HCAs (30-40%)
    
    • low risk of progression to malignancy
  • inflammatory HCAs (40-50%)
    
    • more common in obesity or NAFLD
    • can also be beta-catenin activated (10%)
  • beta-catenin-mutated HCAs (10-15%)
    
    • much higher incidence of turning into malignancy, much rarer
  • unclassified HCAs (10%)
  • ?also Sonic hedgehog HCAs (rare)
• Path
  
  • micro: monoclonal proliferation of well-diff, usu bland-looking hepatocytes containing increased glycogen & fat, arranged in sheets & cords that are usu one, or at most two, cells in width (similar to normal liver but no non-parenchymal liver cells, ie no bile ducts, central veins or Kupffer cells)
  • may transform –> dysplasia –> HCC
    
    • 4.2% malignant transformation overall but 47% in men
    • risk also increased in beta-catenin activation & >5cm
• Clinical: 50% asymptomatic; large (8-15cm) may cause abdo pain/fullness; if >5cm may present w acute onset abdo pain & shock from intraperitoneal rupture
• Imaging
  
  • USS: well-demarcated, hyperechoic (high lipid content), often heterogeneic from haemorrhage, necrosis, fat content
  • CT: often heterogenous due to mixed components of fat, haemorrhage & necrosis
    
    • hypodense on unenhanced CT, enhance on arterial phase, isodense or stay hyperdense on PV & delayed phase
    • peripheral enhancement may be seen on contrast-enhanced CT due to presence of large subcapsular feeding vessels, centripetal pattern
  • MRI: heterogenous
    
    • T1: bright
    • T2: hyperintense predominantly but often heterogenous. Enhance on arterial phase, remains hyperintense or isointense cf surrounding parenchyma on PV or delayed phase
    • may have peripheral rim corresponding to fibrous capsule
  • difference between HCA & HCC: HCC has washout - will become hypodense/hypointense on PV imaging rather than staying hyperdense or becoming isodense
  • PET can differentiate between HCA & FNA well if doubt
• biopsy only if doubt though would need core to work out Bordeaux classification so some do
• Management
  
  • spontaneous rupture w acute haemorrhage: hepatic artery embolisation as temporising measure; once stabilised & resuscitated, laparotomy & resection of mass
  • symptomatic: resect
  • asymptomatic on OCP: stop OCP & watch for regression, espec if <5cm; if persistently >5cm resect
  • surgery if: male, due to metabolic disorder, haemorrhage, symptomatic, increasing size after stopping OCP or not decreasing if already >5cm, >5cm, beta-catenin mutated & inflam HCAs prone to malignant degeneration, diagnostic doubt/increased AFP (some suggest resection prior to planned pregnancy)
• Resection
  
  • don’t need wide margin but do need enough FLR
• Alternatives
  
  • RFA or elective transarterial embolisation
  • liver transplant for exceptional cases
• Follow-up
  
  • usu involute w time, esp if <4cm and after COC is discontinued
  • if not resecting then serial imaging & can also monitor AFP as risk of malignant potential = about HCC

Question 33

Discuss hepatic haemangiomas

Answer 33

• benign mesenchymal tumour
• most common benign liver tumour (second most common liver tumour overall after mets)
• F>M, mean age 45
• giant/cavernous haemangiomas = >10cm
• path:
  
  • micro = composed of multiple blood vessels lined by single layer of endothelial cells within a thin, fibrous stroma (endothelium-lined, blood-filled spaces separated by thin fibrous septa)
  • macro = well-circumscribed compressible tumour w dark colour
  • involution or thrombosis can result in dense fibrotic masses difficult to differentiate from malignant tumours
• Clinical
  
  • most asymptomatic
  • vague sx in larger ones
  • complications include: spontaneous/traumatic rupture (v rare), intratumoural bleeding (rare), consumptive coagulopathy aka Kasabach-Merritt syndrome (thrombocytopenia and hypofibrinogenaemia caused by consumption of coagulation factors), AV shunting wihtin liver leading to cardiac hypertrophy & CHF, rapid growth leading to obstructive jaundice
• Imaging
  
  • USS: well-defined, lobulated, homogenous hyperechoic masses (+/- heterogenous areas from haemorrhage, fibrosis or calcification) & post-acoustic enhancement, accuracy 70-80%, strongly recommend MRI or CT done to confirm
  • CT
    
    • non-con - well-dermarcated, hypodense
    • arterial phase: hyperdense peripheral enhancement/peripheral nodular pattern of enhancement (enhanicng rim) w hypodense centre
    • PV phase: progressive hyperdense peripheral enhancement (enhancement progresses centripetally)
    • delayed phase: ongoign filling/enhancement of lesion cf surrounding parenchyma
  • MRI - better if smaller
    
    • T1 = hypointense
    • T2 = hyperintense bc fluid in lesion - lightbulb sign
    • contrast pattern similar to CT - hypointense on non-con, nodular peripheral enhancement which slowly fills in towards lesion on portal venous phase, ongoing enhancement in delayed phase
  • overall discontinuous rim unlike in an abscess & must match phase eg PV phase matches portal vein, arterial phase matches artery)
• NO BIOPSY
• Management
  
  • reassure if asymptomatic & <4cm - most stable over time
  • indications for invervention
    
    • consider if very large, growing (?>10cm) but risk of rupture pretty negligible
    • symptmoms
    • rare things - Kassabach-Merritt, high output CHF, obstructive jaundice
  • if intervention: enucleation preferred, otherwise complete surgical resection
    
    • RFA w or w/o preop arterial embolisation
    • liver transplant v rarely for complicated, giant haemangiomata
• Nat hx: most remain stable for long time. Can increase w pregnancy but no assoc w OCP

Question 34

Discuss imaging appearances of liver lesions

Answer 34

• Cyst
  
  • Hypovascular, non-enhancing, on MRI T2 bright
• FNH
  
  • Central scar
  • Homogenous, hypodense on precontrast; then rapid diffuse enhancement w centrifugal filling w central scar not enhancing; then becomes isodense & fades into rest of liver in venous delayed imaging while hyperattenuation of scar often seen
  • central scar in fibrolamellar HCC in comparison is low attentuation on T2 MRI
• HCA
  
  • Hypodense on pre-contrast phase, enhancement on arterial phase, hypo/isointensity on PV & delayed phase
  • May appear heterogenous depending on how much fat, haemorrhage & necrosis there is
    
    • T1: bright
    • T2 and CT: hyperintense predominantly but often heterogenous. Enhance on arterial phase, remains hyperintense or isointense cf surrounding parenchyma on PV or delayed phase
    • may have peripheral rim corresponding to subcapsular vessels, centripetal pattern
  • difference between HCA & HCC: HCC has washout - will become hypodense/hypointense on PV imaging rather than staying hyperdense or becoming isodense
  • PET can differentiate between HCA & FNA well if doubt
• Haemangioma
  
  • Often hypointense/hypodense on precontrast; nodular peripheral enhancement on arterial phase, further centripetal filling on PV, usu continued filling on delayed phase
  • Lightbulb sign on T2 MRI given blood/fluid within it
• HCC
  
  • Often hypointense/hypodense on precontrast imaging but brisk arterial enhancement & washout meaning darker than surrounding liver parenchyma on PV imaging (bc of 100% hepatic artery blood supply)
  • Contrast washout = HCC
• Cholangiocarcinoma
  
  • Often hypodense on original precontrast imaging, may have some rim enhancement; in PV and delayed phases often hypoenhancing. Hard to differentiate from CRC mets
• Metastatic cancer
  
  • Varies; in general (incl CR) usu hypodense & don’t have a lot of enhancement or just rim enhancement & rapid washout
  • but can also get hypervascular tumours incl mucinous adenocarcinoma, RCC, melanoma, neuroendocrine tumours

Question 35

Discuss intrahepatic cholangiocarcinoma

Answer 35

• Definition = cholangiocarcinoma arising from peripheral intrahepatic biliary radicles (exlcudes tumours arising from biliary confluence or first-order branches)
• risk factors
  
  • traditionally chronic biliary inflammation eg PSC, chronic choledocho, hepatolithiasis, parasitic, Caroli’s disease, choledochal cyst
    
    • but >95% dont’ have these
  • newer risk factors: chronic non-alcoholic liver disease, HBV, HCV, diabetes, metabolic syndrome
    
    • but 75% have normal livers; 16% chronic hepatitis/liver fibrosis; 9% cirrhosis
• Classification
  
  • macroscopic findings
    
    • mass-forming (most common)
    • periductal-infiltrating (spreads along ducts)
    • intraductal-growth type (intraluminal spread)
  • AJCC staging
• Path
  
  • 2 precursors to invasive cholangiocarcinoma but seen more freqeuntly in large bile ducts eg hilar tumours
    
    • flat or micropap growth of atypical biliary epithelium (biliary dysplasia or biliary intraepithelial neoplasia)
    • intraductal papillary neoplasm of bile duct - prominent papillary growth of atypical biliary epithelium w distinct fibrovasc cores & frequent mucin overproduction
• Clinical: tends to present at advanced stage; though from small ducts, jaundice can be present if tumour compresses or invades biliary confluence
• Imaging
  
  • fibrous tumour therefore no enhancement on arterial phase & delayed enhancemen t during late phase - on both CT & MRI
  • MRI - hypointense on T1, mod-markedly hyperintense on T2
  • typically large, non-encapsulated, heterogeneous, w narrowing of adjacent portal veins & retraction of liver capsule
  • satellite nodules form as tumour grows
  • high propensity for LN invasion
  • main ddx: other fibrous tumours & in particular CRC mets
• Mx
  
  • surgical resection = only cure - frequently extensive
  • no current role for liver transplant

Question 36

Discuss liver cystadenomas and cystadenocarcinomas

Answer 36

• cystadenoma = rare neoplasm generally manifested as large cystic mass; cystadenocarcinoma = extremely rare malignant neoplasm
• Incidence:
  
  • cystadenoma almost always in women >40yrs
  • cystadenocarcinomas M=F & more aggressive in men
• Path:
  
  • usually multilocular; globular external surface w multiple protruding cysts & locules of various sizes
  • benign/atypical cuboidal to columnar epithelium & in 95% content is mucin
    
    • previously thought all had ovarian-like stroma but 15% don’t
  • epithelium often forms polypoid or papillary projections
  • cystadenomas grow slowly but precursor to cystadenocarcinoma; 10% of resections for ‘cystadenoma’ = malignant
• investigations
  
  • imaging: cystic structure w varying wall thickness, nodularity, septations, fluid-filled locules
    
    • difficult to distinguish the two pre-op; presence of calcs + mixed solid/cystic components, large projections, markedly thickened wall on imaging, mural or septal nodule, nodule diameter >10mm = assoc w cystadenocarcinoma
  • don’t biopsy - limited sensitivity, doesn’t change management, risks seeding
• management
  
  • complete tumour excision - both to get definitive histo and to prevent malignant transformation

Question 37

Discuss neoadjuvant chemo for liver mets

Answer 37

• resectable metachronous CRLM
  
  • data conflicting
  • potential advantages: facilitating resection of large tumours & assessing tumour response to chemo
  • potential drawbacks: progression of disease, possible increased risk of post-resection complications & liver insufficiency (but data suggests delaying surgery for chemo won’t result in resectable liver mets becoming unresectable & if pts do develop new extrahepatic lesions while on chemo this may have helped identify pts w aggressive tumour biology who surgery wouldn’t have been beneficial for)
  • EORTC 40983 trial - periop FOLFOX decreased non-therapeutic laparotomy bc of extensive disease, higher postop complications but not post-op mortality & increased progression-fre esurvival at 3 and 5yrs but no difference in 5yr OS
  • FOLFOX, FOLFIRI, XELOX all acceptable
  • usu 4-6wks chemo & liver resection ≥4wks after finishing chemo
• unresectable metachronous CRLM
  
  • neoadj chemo may downstage & allow resection
  • FOLFOXIRI may be best, ?EGFR/VEGFR inhibitors in select pts
  • resect when mets become clearly resectable but delayed at least 4wks after completion
  • 40-50% CRLM w complete rad resopnse had viable tumour
• synchronous CRLM
  
  • neoadj chemo may identify pts w aggressive tumour biology
    
    • size of majority of met lesions & primary either decreases or remains stable; widespread progression may be contraindication to subsequent liver resection
  • if unresectable mets may downstage
  • options for timing of hepatic resection (no evidence for advantage w any approach, tailored)
    
    • simultaneous resection of primary w liver mets
      
      • tends to be assoc w shorter total LOS & less morbidity w comparable 5yr survival
      • relative contraindications: multiple bilateral mets, inadequate FLR or when extensive operations anticipated for either primary or metastatic disease
      • tho may be able to do first part of 2-stage hepatectomy
    • resection of primary first & liver mets later
      
      • if symptoms related to primary
    • resection of liver mets first

NB neoadj chemo espec oxaliplatin & irinotecan reuslts in liver changes - steatosis, steatohepatitis & sinusoidal dilatation/sinusoidal obstructive syndrome - delay surgery at least 4-6wks after chemo, tolerance of major liver resection may be reduced

Question 38

Discuss the classification of Hepatic Cysts

Answer 38

Congenital

• Simple cysts - contain serous fluid
• Polycystic disorder - in assoc. with PCKS

Infective

• Hydatid cyst
• Pyogenic or amoebic abscess

Neoplastic

• Benign = Cystadenoma - cuboidal epithelium
• Malignant = Cystadenocarcinoma, IPMN of bile duct, primary liver ca with cyst degeneration, cystic mets to liver - colorectal, neuroendocrine, GIST, SCC, breast

Post-traumatic

NB cysts can be:

• simple - solitary or polycystic
• complex - multilocular/sepated/irregular lining, papillary projections
  
  • neoplastic (cystadenoma/cystadenocarcinoma) or echinococcal

Question 39

How can pancreatic cystic lesions be classified?

Answer 39

Inflammatory fluid collections

• Acute peripancreatic fluid collection
• Pancreatic pseudocyst
• Acute necrotic collection
• Walled off pancreatic necrosis

Non-neoplastic pancreatic cysts

• True cysts/benign epithelial cysts (v rare)
• Retention cysts
• Mucinous non-neoplastic cysts
• Lymphoepithelial cysts

Pancreatic cystic neoplasms

• Mucinous cystic neoplasm
• Serous cystic neoplasm
• Intraductal papillary mucinous neoplasm
• Solid pseudopapillary neoplasm

Cystic degeneration of solid pancreatic tumours eg endocrine, acinar cell carcinoma, ductal carcinoma

Question 40

How do you assess portal pressure?

Answer 40

• Subjective: platelet count, splenic length (>13cm), portal vein diameter (>13mm)
• Indirect: gastric varices
• Direct:
  
  • transjugular hepatic venous pressure gradient (>10mmHg)
  • direct portal vein puncture
  • splenic pulp pressure

Question 41

How does hepatic cystic echinococcus present?

Answer 41

Asymptomatically

• Picked up incidentally on USS or CT

Uncomplicated disease

• Hepatomegaly
• RUQ pain
• Nausea/vomiting

Complicated disease

• Abscess
• Cholangitis
• Jaundice
• Anaphylaxis
• Fistula

Question 42

How is Gallbladder trauma classified?

Answer 42

• Contusion (likely under-reported)
• Perforation (most common)
• Avulsion
• Traumatic cholecystectomy

Question 43

How should symptomatic gallstones in pregnant women be managed?

Answer 43

• WSES guidelines 2020 say: best option should be chosen considering balance among risk of complications from ACC, limitations on medication availability depending on trimester, risk of relapse, risk of other specific conditions which may occur during pregnancy & the time until delivery or maturation of the foetus; in general, in absence of contraindications, surgery is suggested as first-line in order to avoid complications and potential drug toxicity for foetus
  
  • Retrospective studies say recurrent ACC or pancreatitis can occur in 10% while miscarriage can occur in 10-20% of pts
  • Non-op mx is alternative option but risk of higher incidence of spont abortion, threatened abortion and premature birth cf pts who underwent cholecystectomy
  • Within limitations of quality of studies, laparoscopy should be suggested for tx of symptomatic gallstones incl ACC
  • Vast majority of studies suggest 2^nd trim – first part of 3^rd trimester as best time to do lap chole, as higher risk of miscarriage & toxic effect of anaesthesia in first trimester, while concerns are related to size of uterus in third trimester
  • British guidlelines 2019 confirm benefits of lap chole over non-op tx, espec in 2^nd trimester
• Natural hx
  
  • If pt treated non-op (Lu, Am J SUrg 2004)
    
    • Relapse rate of biliary disease ~30-40% overall? But trimester dependent
      
      • Up to 1^st trim –55-92%, 2^nd – 55-64%, 3^rd – 40-44% (Swisher Am J Surgy 1994, Jelin Surg Endosc 2008)
      • NB if pt had pancreatitis – 70% risk of recurrence (during pregnancy)
    • Preterm delivery in up to 17%
  • Pre-term labour may occur several weeks post-op
• periop considerations:
  
  • position pt with L lateral tilt, to alleviate impaired venous return via SVC
  • take care with trocar insertion – supraumbilical Hasson
  • maintain pressures <12mmHg
  • ?give steroids (for foetal lung maturity), in case of preterm delivery
• ERCP is an option in pregnancy (with uterus shielded +/- avoid/minimize fluoroscopy, esp in first trim)… but there are risks to foetus (rad risks * risks from any subsequent pancreatitis) à risk of death 0.2% but risk of prem birth 0.4% (Medscape 2011)

Question 44

Imaging characteristics and management of simple liver cysts

Answer 44

• USS - can be diagnostic; circular area with well-defined border, no vascularity in cyst, posterior acoustic shadowing (nodularity or septations worrying, though thick or nodular wall can also occur in haemorrhage)
• CT - hypodense cf surrounding parenchyma, smooth, non-enhancing/no uptake on arterial phase bc avascular, no internal structure
• MRI
  
  • T1 - low signal intensity (hypointense cf surrounding parenchyma)
  • T2 - extremely high signal intensity/bright, which doesn’t enhance after contrast
• Asymptomatic - no treatment (no malignant potential)
• symptomatic
  
  • perc aspiration considered only to clarify if pain is related to cyst (recur)
  • perc aspiration + sclerotherapy
  • consider primary surgical approach if difficult to r/o cystadenoma or malignancy, or if biliary communication
    
    • surgical deroofing or fenestration of portion of cyst that is extra-hepatic
      
      • if histo of partially removed cyst wall abnormal or suggestive of cystadenoma, need hepatic resection
    • formal anatomical resection - consider if cyst v large, concern re thick-wall, nodularity or septations, or if intracystic haemorrhage bc suggestive of malignant component

Question 45

Investigations for HCC

Answer 45

• AFP increased in 50% (may also be increased in cirrhosis)
  
  • <300 = non-specific; >400 = diagnostic w 95% confidence; v high levels usu indicate aggressive tumour
  • chronic active hepatitis may increase AFP but almost never >4000
  • 20% HCC non-producers & only 10% small tumours have raised levels
  • other tumours asso w AFP: non-seminal germinal tumours, hepatoid gastri tuours, neuroendocrine tumours
• USS - significant role in screening but need CT or MRI for definitive dx & treatment planning
  
  • nodules <1cm - short interval surveillance period eg q3mo til lesion disappeared, enlarges or displays characteristics of HCC
  • nodules 1-2cm: do contrast-enhanced triple-phase CT & MRI
• CT
  
  • early enhancement on arterial phase with washout in delayed phases = presumed HCC (intrahepatic cholangiocarcinoma shows delayed enhancement)
  • usu hypodense
  • mosaic appearance w fibrous septa separating areas of variable attenuation, representing internal regions of haemorrhage, necrosis, fatty degeneration & fibrosis
  • fibrous capsule has low attenuation on unenhanced imagines & enhances on PV phase
• MRI
  
  • variable appearance on unenhanced T1 (usu hypointense)
  • typically hyperintense on T2-weighted & DWI but again vary
  • after gadolinium, characteristic ealry enhancment on artieral phase imaging & washout on delayed images –> hypointense cf surrounding parenchyma
• PET only useful in metastatic HCC
• biopsy
  
  • not always required if appropriate risk factors & suggestive rad featrues, w or w/o increased AFP
  • if biopsy required should be transhepatic & preferably in an area for future excision

Question 46

Is resection or transplant better for HCC?

Answer 46

• transplant gives better 5yr survival (70% vs >50%) (removes lesion as well as field change/abnormal liver)
• but 20% get delisted from waitlist while waiting because progression of disease so sample
• option to resect and salvage with a transplant if there is recurrence

Question 47

Management of gallbladder at time of gallstone ileus

Answer 47

• Usu GB should be left undisturbed at the original op as cholecystectomy à ­ed M+M (in pts who are already often elderly/frail preop)
  
  • Intense inflam process in RUQ may complicated the cholecystectomy & duodenal repair
  • Once the pt has recovered à an elective cholecystectomy can be considered if pt c/o sx (~30%)… and/or if other stones remain in GB
  • In v fit pts, can consider cholecystectomy at first op (though this is debated); S Connor says more recently a single definitive procedure has been advocated given high reported rates of recurrence & cholangitis, but most recommendations are based on small pt series
  • S connor says definitive simultaneous or metachronous mx of GB may be determined by symptoms and presence or absence of cholecystolithiasis or choledocholithiasis
    
    • In those w a clear CBD & empty GB, spontaneous closure of fistula may occur
    • If choledocholithiasis only, endoscopic mx of this by stone extraction +/- temporary covered stenting of a patent cystic duct may be appropriate
    • In pts w persistent cholecystolithiasis the GB is likely to be shrunken & therefore formal dissection of the hepatobiliary triangle may be hazardous – simply opening fundus, extracting stones, performing a cholangiogram (to ensure a clear CBD), closing cystic duct if patent from within then closing duodenal fistula either primarily or w an omental patch would be standard of care
    • Failure to assess common duct may result in cholangitis once fistula is closed if distal CBD obstruction remains

Question 48

Work-up for gallbladder cancer

Answer 48

• Ca19-9, CEA, LFTs
• USS not accurate
• Cross-sectional imaging ?CT usu ok
• EUS not as good as cross-sectional imaging but better than ultrasound
• staging CT
• PET not routinely used
• consider staging laparoscopy if >pT1b but don’t need biopsy if suspected on imaging - can have false negs and may spread tumour into preitoneum
• cystic duct, CBD, hepatic artery & portal vein nodes are considered locoregional (paraaortic, paracaval, SMA and celiac LNs considered distant mets)
• tumour resectable if no: distant spread (peritoneum, discontiguous liver lesions), tumour involvement of hepatic vasculature or biliary tree that would preclude complete resection, presence of disease in distant LN groups

Question 49

Management of hydatid liver cyst

Answer 49

• depends on cyst stage as classified by WHO - see table, as well as the size, location, complications and overall health of the patient
• medical mx
  
  • at least 3mo of anti-helminthic drug eg albendazole - 400-600mg BD (trying to kill parasite by impairing its glucose uptake)
• surgery
  
  • reserved for large (>5cm), multiple daughter cysts, superficially located or infected, communicating w biliary tree or exerting mass effect on adjacent structures
  • all pts need pre-op albendazole; ideally 3mo but at least 1mo to try sterilise cyst before surgery - reduces complications if cyst spilt & reduces risk of recurrence
  • options
    
    • resect cyst whenever possible (= cure)
      
      • anatomical hepatectomy
      • peri-cystectomy (removal of whole cyst incl wall) - if close to other structures risks injury; if large may prefer anatomical resection
      • removing just endocyst within pericyst - not as good
    • or aspirate cyst at operation, make sure no bile, then inject scolicidal agent; then open & aspirate all daughter cysts w/o spilling them (protect around with hypertonic saline)
      
      • scolicidal options include hypertonic saline, ethyl alcohol, betadien, hydrogen peroxide
      • Principles: eradication of parasite pre-op, adrenaline & steroids available for anaphylaxis, protect peritoneal cavity with hypertonic saline packs, eliminate all viable elements of cyst (suction of contents, inspection of cyst cavity to make sure no communication w biliary tree & if not inject scolicidal agent into cyst), obliteration of residual cavity (can be marsupialised, packed w omentum or plicated)
• PAIR - percutaneous aspiration, injection of chemicals and reaspiration
  
  • not used as much due to risk of anaphylaxis & risk of sclerosing cholangitis if communication w biliary system
  • cyst punctured under USS guidance, cyst fluid aspirated, protoscolicidal agent eg hypertonic saline/ethanol injected, fluid re-aspirated
  • useful for simple cysts in deep location
  • modification = placement of broad tube to remove solid components of cysts as well as daughter cysts

Question 50

Management of non-CRC liver mets

Answer 50

NETs

• liver resection for metastatic NETs improves OS cf supportive care, and R1 & R2 resections give 5yr survival rates of 70% and 60%
  
  • cytoreduction aims to reduce tumour volume by ≥90% if R0 not feasible
  • don’t need formal resection with wide margins - enucleation & wedge resection sufficient
  • aggressive approach, sometimes combining liver resection & other ablative strategies (eg cryoablation & RFA) = warranted
• non-surgical tx modalities include RFA, TAE, TACE
• systemic treatment options include
  
  • somatostatin analogues (symptomatic relief & improvement in PFS)
  • systemic platinum-based chemo (response rate of 67% in grade 3 but survival benefit limited & signif toxicity)
  • sunitinib (receptor tyrosine kinase inhibitor), everolimus (mTOR inhibitor), bevacizumab (anti-VEGF)
• liver transplant = emerging option but controversial & concerns remain re tumour recurrence in context of immunosuppression

Non-CRC, Non-NET mets

• general principles to consider re resection = similar to those for metastatic CRC; FLR, poor prognosis if extrahepatic disease, multiple tumours, large tumours or a short disease-free interval
  
  • consider in well-selected pts w genitourinary mets
  • breast, melanoma & sarcoma pts rarely present w isolated liver mets but w a long disease-free interval or long-term stability on chemo, liver resection can be considered
  • in general, liver resection for metastatic non-CRC, non-NET tumours has to be considered cytoreductive
  • GISTs: liver mets usu unresectable so imatinib usu first line; if tumour respnods after 6-12mo can consider resection if R0 resection possible
    
    • disease rpogression: imatinib dose escalation, then 2nd line (eg sinitinib) & 3rd line agents
    • if resectable, no good evidence but in retrospective series 5yr survival rates >70% w combo of surgery & imatinib
• can also consider RFA, MWA, TAE, TACE, systemic therapy, immunotherapy

Question 51

Management of post-ERCP perforation

Answer 51

• principles of operative management:
  
  • control sepsis - drain retroperitoneal/abdominal collections, remove stones, drain biliary tree
  • repair perforation
• wire/basket perfs - usu heal w non-op rx
• periampullary perforations: mx controversial
  
  • early conservative mx: NBM, NG, abx, frequent rv/repeat CT
  • +/- consider endoscopic stent placement… or PTC - to divert bile away from injury
  • perc drainage of any collections which subsequently form
  • indications for operative mx:
    
    • failure of non-op rx
    • documented perf with retained stones/instruments
    • large free/retroperitoneal collections or ongoing leakage
    • increasing peritoneal signs/suspected suppuration/peritonitis
• duodenal perfs: generally require operative repair
  
  • if early: 1 or 2 layer transverse closure +/- omental patch
  • if late: consider
    
    • Bilroth II and duodenal stump drainage or
    • repair defect & do a pyloric exclusion (suture from inside via a gastrotomy) with gastroenterostomy

Question 52

Management of unresectable CLRM

Answer 52

• median survival approaching 3yrs in some trials
• chemo
  
  • systemic palliative chemo can improve QOL & prolong survival
  • can use FOLFOX, FOLFIRI or XELOX - relatively similar efficacy
  • FOLFOXIRI recommended in young pts w severe sx, high tumour burden or contraindications to biologic agents (better RR, PFS, OS)
  • may add bevacizumab (in some trials increases PFS & OS)
    
    • caution if elderly w prev arterial thromboembolic events or pts w recent major surgery
  • or may add anti-EGFR meds eg cetuximab if inoperable wild-type KRAS metastatic CRC
    
    • but bevacizumab preferred if RAS/BRAF mutated tumours, pts w markers of anti-EGFR resistance, right-sided primary tumours
• HAI chemo
  
  • limited to pts w isolated liver lesions not amenable to resection of ablation but role uncertain
  • complications: biliary sclerosis, chemical hepatitis, arteiral thrombosis, infection, catheter displacement, gastroduodenal or GB inflammation
• other hepatic artery-based strategies: TACE & Y-90 TARE have primising early results
• ablation therapy
  
  • RFA most common (resection better if possible)
    
    • limitations in tumours located close to major blood vessels & other vital structures, tumours >3cm
    • so not recommended as first line for unresectable CRLM espec if extrahepatic disease
  • MWA - same limitations
  • complications: bleed/haematoma, vascual injury, abscess, biliary fistula
• radiation tehrapy
  
  • effective antitumour dosage of traditional external beam rad therapy = v toxic to normal liver parenchyma
  • development of techniques using targeted rad eg sterotactic body radiotherapy has provided new opportunity for local control of CRLM

Question 53

Options for increasing FLR

Answer 53

• pre-op portal vein embolisation
  
  • eg embolising R portal vein –> hypertrophy of left liver lobe & facilitates extended R hepatectomy 6wks later
  • usually well tolerated bc of dual supply of liver & complications uncommon
  • can be adapted to enable 2-stage procedure eg if required R hemihepatectomy & multiple resections from L hemiliver
• ALPPS (Associating Liver Partition & Portal vein ligation for Staged hepatectomy)
  
  • more recent evovlution of principle of 2-stage resection; a short-interval, two-staged liver resection
  • 1st stage = open right PVL an din situ parenchymal transection in the right trisectionectomy plane (between segment 2/3 and seg 4)
  • 2nd stage done 1-2wks later and involves right trisectionectomy
  • ALPPS produces accelerated hypertrophy in FLR in much shorter time interval (growth rate 11x higher) but only done in specialist high-volume centres
  • advantages = improved hypertrophy rates & higher proportion of pts completing the 2-staged treatment but additional operative risk

Question 54

Outline your approach to gallbladder polyps

Answer 54

Question 55

Pathology of HCC & nodular lesions in chronic liver disease

Answer 55

Preneoplastic lesions

• dysplastic foci = microscopic lesions composed of dysplastic hepatocytes <1mm in size; occur in chronic liver disease, particularly cirrhosis
• dyplastic nodules = nodular region <2cm in diameter w dysplasia
  
  • low-grade DNs ~1cm diameter - low probability of becoming malignant
  • high-grade DNs = up to 2cm, less common, often difficult to differentiate from highly differentiated HCC - become malignant in 1/3 cases (remember lesions <2cm can also represent HCC)

HCC

• solitary vs multinodular (doens’t affect prognosis); may form
  
  • large solitary circumscribed nodule w or w/o adjacent smaller satellite nodules
  • in cirrhosis may be multinodular within one lobe
  • or may infiltrate liver diffusely w/o forming circumscribed nodules (ie diffuse, expansive, infiltrative, multifocal etc)
• WHO tumour type classification - subtypes
  
  • fibrolamellar, scirrhous/sclerosing, clear cell type, steatohepatitic, macrotrabecular massive, chromophobe, neutrophil rich, lymphocyte rich etc
• degree of differentiation (Edmonson-Steiner grading): well, moderately, poorly differentiated or undifferentiated
• molecular pathogenesis
  
  • TERT promoter mutations = most frequent (60%) observed in HCC development & progression - subsequent increase in telomerase expression = a determinant of malignant transformation
• vascularisation = key parameter in differentiating HCC from regenerating nodules; progression from macroregenerative nodule –> low grade DN, high grade DN & frank HCC = characterised by loss of portal tracts & development of new non-triadal arterial vessels which become dominant blood supply in overt HCC lesions
  
  • this arterial neoangiogenesis = landmark of HCC diagnosis & rationale for chemoembolisation & anti-angiogenic treatment
  • HCC derive 100% of bld supply from hepatic a
• capsule - in 80% HCC the tumour nodules are surrounded by a distinct fibrous capsule
• HCC has great tendency to spread locally & invade blood vessels
  
  • rate of portal invasion higher in expansive type, poorly differentiated HCC & large tumours
  • presence of portal invasion = most important predictive factor assoc w recurrence
  • once HCC invades portal vein, tumour thrombi grow rapidly in both directions –> tumour fragments spread throughout liver
  • once tumour thrombus extended into main portal vein, high risk of complete thrombosis & portal HTN -> oesophageal varices or liver decompensation
  • invasion of hepatic veins less frequent but eventually extends into suprahepatic vena cava or RA, assoc w high risk of lung mets
• rarely HCC may invade biliary tract –> jaundice or haemobilia; mechanisms of biliary obstruction:
  
  • intraductal tumour extension
  • obstruction by fragment of necrotic tumour debris
  • haemorrhage of tumour –> haemobilia
  • metastatic LN compression of major bile ducts in porta
• extrahepatic mets: lungs first then adrenals, bones, LNs, meninges, pancreas, brain kidney

Question 56

Pathophysiology of cholecystitis

Answer 56

• Aetiology of cholecystitis – 4 possible causes
  
  • 95% due to stone obstructing neck of GB
  • loss of mucosal integrity – secondary to immunocompromised or invasive microbial infection
  • torsion due to gallbladder hanging on mesentery
  • gallbladder artery ischaemia due to arterial occlusion or hypoperfusion
• Pathophysiology of cholecystitis
  
  • Prolonged obstruction of cystic duct by gallstones/sludge (impacted in neck) leads to ­ release of prostaglandins/mucus within the GB mucosa resulting in fluid secretion à mucocele +/- triggers =cycle of ­ed distension & further mucosal damage and inflammation
  • Days 2-4 get oedematous cholecystitis – increased blood flow, evidence of oedema within the wall, active inflammation/bacterial translocation
    
    • Apparently secondary bacterial infection of stagnant pool of bile occurs in ~20% of cases
      
      • Enterobacteriaeceae (E coli, Klebsiella, Enterobacter) most common, also enterococcus
      • May result in empyema
    • Can go on to get suppurative cholecystitis w at days 7-10 active evidence of repairing inflammation, proliferation of fibrosis, intra-mural abscess
  • Or days 5-7 necrotising cholecystitis – increased wall pressure à ¯blood flow, venous ischaemia w evidence of vascular thrombosis, patchy mucosal necrosis occurs
    
    • If complicated by infection w a gas-forming organism, acute emphysematous cholecystitis
  • Progressive full-thickness necrosis results in either
    
    • Contained pericholecystic abscess, either contained by colon/duodenum or ruptures into liver
    • Or free perforation of GB due to full-thickness necrosis resulting in biliary peritonitis
  • If oedematous cholecystitis phase resolves, but you get repeated episodes, end up w chronic cholecystitis – fibrosis, shrunken GB, evidence of chronic inflammation; and can progress to cholecysto fistula to CBD, duo, abdo wall, colon
  • Pathology of acalculous cholecystitis
    
    • Thought to be vascular in origin (ischaemia due to shock/DM vascular disease) –> small vessel thrombosis / occlusion (cystic artery is end-organ artery w no collateral circulation and can get microvasc occlusion of end arteries within GB wall)then +/- progression to gangrenous cholecystitis +/- secondary bacterial invasion… (E Coli/Clostridia)
    • SC says not well understood, thought to be due to combo of change in bile salt composition, loss of mucosal integrity & microcirculatory disturbances

Rarely, Salmonella typhi may cause acalculous cholecystitis

Question 57

Pathophysiology of gallstone formation

Answer 57

• bile = 97-98% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids and lecithin) and inorganic salts
• gallstones form due to an imbalance of 3 key products in the bile: bile salts, lecithin and cholesterol
• 3 major factors explain most gallstone formation:
  
  • supersaturation of secreted bile which causes crystallisation
    
    • cholesterol precipitates out into crystal when the amount of cholesterol exceeds the capacity of bile salts & lecithin to contain it in micelles
    • increased unconjugated bilirubin as a result of increased enterohepatic circulation of bili from excessive breakdown of RBCs –> increased bilirubin conc in bile –> precipitation of calcium bilirubinate to form black pigmented stones
  • crystal formation is further accelerated by pronucleating agents, including glycoprotiens & immunoglobulins/mucin
  • hypomotility increases stasis in the gallbladder, allowing more time for solutes to precipitate
• once formed the stones persist and enlarge or consolidate over time
• pts w ileal disease/post resection can get
  
  • pigment stones from increased bile salt delivery to the colon (increased enterohepatic cycling)
  • or cholesterol stones bc of excessive bile salt excretion in faces & diminished bile salt pool so cholesterol precipitates out
• brown pigment stones occur due to stasis within the CBD with associated bacterial infection usually
  
  • obstruction
  • Caroli’s disease
  • PSC
  • biliary infection
  • mostly seen in south-east asia

Question 58

Porcelain gallbladder

Answer 58

• extensive calcium encrustation of GB wall
• more common in women
• aetiology
  
  • 95% assoc w gallstones
  • pathogenesis controversial; ?chronic inflammation due to gallstones leading to scarring, hyalinisation & calcification
  • or cystic duct obstruction leading to bile stagnation within GB followed by mucosal precipitation of alcium carbonate saltes
• classification - by extent of calcification
  
  • complete intramural calcification: continuous band of calcium infiltrates & replaces muscular layer of gallbladder wall; accompanied by sloughing of mucosal epithelium & dense fibrosis of entire GB wall
  • selective mucosal calcification
• incidence of malignancy 2-3%; higher with selective mucosal calcification vs complete type
• some say do lap chole for all; others say do it if symptomatic or selective mucosal calcification (but if young with complete mural calcification would prob offer it)

Question 59

Prevention of bile duct injury

Answer 59

• risk 0.1%
• routine use of 30 degree scope
• cephalad retraction on fundus to 10 o’clock position to reduce redundant infundibulum
• lateral traction on GB to place cystic duct perpendicular to CBD
• avoid dissection at/below Rouviere’s sulcus (a landmark/fissure between R lobe and caudate process which lies at level of porta hepatis where right pedicle enters the liver; visible in 80% of pts
• careful use of diathermy
• dissect as close to GB as possible
• avoid cauterising or clipping arterial bleeding blindly - most bleeding can be controlled w a few mins of direct pressure w a lap forceps compressing Hartmann’s pouch onto the bleed point
• no division or clipping without identificationobtain critical view:
  
  • Calot’s triangle cleared of fat and fibrous tissue
  • lower third of GB separated from liver to expose cystic plate
  • demonstration of 2 and only 2 structures to be seen entering GB
• in severe inflammation, consider
  
  • subtotal cholecystectomy

Question 60

Pyogenic liver abscess

Answer 60

• Aetiology
  
  • biliary tree (most common, 38%)
    
    • biliary obstruction –> bile stasis w potential for bacterial colonisation, infection, ascension into liver)
  • direct extension (1%)
    
    • eg cholecystitis, subphrenic abscess, perinephric abscess, perforation of bowel into liver
  • portal vein bacterial seeding (<5%)
    
    • pyelophlebitits (PV infection) from drainage of GI infection - appendicitis, diverticulitis, pancreatitis, IBD, CRC
  • arterial haematogenous seeding (<5%)
    
    • any systemic infection - endocarditis, pneumonia, OM
  • traumatic (5%)
    
    • blunt or penetrating trauma -> intrahepatic hematoma or necrosis -> abscess (bacteria may be introduced by trauma or seeded from elsewhere
    • hepatic artery embolisation or thermal ablative procedures
  • cryptogenic (43%)
    
    • no cause found
  • pathogens: E coli, Klebsiella, Bacteroides, Enterococci eg Step faecalis, anaerobic strep
• Risk factors: dibeetes, underlying hepatobiliary/panc disease, chronic renal failure, liver tranpslant, immunosuppression, IBD, goegraphic factors, colorectal neoplasia (monomicrobial klebsiella infections)
• Path
  
  • 75% right hemiliver
• Clinical: remember endogenous endophthalmitis (rare complication specific to Klebsiella) - serious, more common in diabetes, can lose sight
• Investigations
  
  • send echinococcus serology & antigen testing to r/o
  • send Entamoeba histolytica specific antigen or PCR testing
  • stool culture for ova, cyst, parasites
  • USS - may be hypo or hyperechoic +/- int echoes/septations
  • CT - gold standard (MRI equally sensitive but not often done)
    
    • well-defined lesion w central hypoattenutation & often w IV contrast will have hypernhancement of ring; can be complex w lobulations/subcollections, can have irreg border
    • complications of abscess eg thrombosis of nearby vessels, rupture of abscess, also looks for causes in rest of abdomen
  • need to differentiate bc pyogenic mainly tx by abx & drainage, amoebic by abx, echinococcal by surgery
• Management
  
  • abx after blood cultures; if >3cm perc drain
  • surgery if failed perc drainage (more likely if multiloculated) or ruptured abscess or if pts need surgical tx of primary pathologic process

Question 61

Recurrent pyogenic cholangitis

Answer 61

• definition = recurrent bacterial cholangitis caused by cholangiohepatitis or intrahepatic stones
• incidence: East Asia, 3-4th decade, M-F
• aetiology:
  
  • ?underlying susceptibility to cholangiohepatitis or intrahepatic stones from ?helminthic infections (flukes) or ?as a consequence of malnutrition –> enzyme deficiencies –> increased unconjugated bili
• clinical:
  
  • fever, RUQ pain, jaundice
  • bc the infection, inflammation & stones commonly present in a segmental or lobar pattern, the jaundice tends to be mild
  • bloods similar to other causes of cholangitis
• pathology
  
  • biliary pathogens eg Clonorchis sinensis (liver fluke) & Ascaris lumbricoides (round worm) populate biliary tree –> these and other pathogens secrete an enzyme that hydrolyses water-soluble bilirubin glucuronides to form free bilirubin –> this then precipitates to form brown pigment stones using a nidus such as small cholesterol crystals, black stones from the GB, parasite eggs & dead worms or flukes
  • these stones may partially or fully obstruct the biliary tree, causing recurrent episodes of cholangitis (+/- haemobilia) & eventually abscesses or even cirrhosis
  • resultant patchy/focal dilatation & strictures of intra- and extrahepatic ducts
  • increased risk of cholangiocarcinoma
  • unclear whether primary inciting event is infection causing inflammatory stricture or inflammatory stricture w subsequent infection of stagnant bile

Liver flukes (trematodes)

• Aetiology
  
  • Infestation w liver flukes is caused through consuming inadequately cooked, pickled or salted infected fish
  • immature fluke passes into the biliary tree, where it grows to maturity
  • ova passed into GI tract & subsequently to water supplies, infecting molluscs & fish
  • infection w Clonorchis sinensis in China, Japan & south-east Asia; Opisthorchis viverrini found in parts of Eastern Europe & Siberia
• Clinical: asymptomatic or present w acute febrile illness or chronic symptoms
  
  • Chronic infestation à hepatolithiasis
• Ix:
  
  • detection of ova within stool or in duodenal aspirates
  • eosinophilia may also be present on blood film
  • ERCP – slender filling defects within bile duct + assoc changes of fibrosis & calculus formation

Ascaris lumbricoides

• Roundworm Ascaris lumbricoides = commonest worm to infect humans
• Clinical: rarely, an infected pt can present w obstructive jaundice due to migration of the worm into the biliary tree – difficult to distinguish from stone disease
• The more frequent presentation is from cholangitis due to the worm traversing the ampulla
• Ascaris has also been associated w recurrent pyogenic cholangitis
• Ix:
  
  • USS sometimes identifies a long, linear filling defect within biliary tree
  • ID may occur at ERCP where endoscopic extraction may be possible
• Mx
  
  • Antihelmintics – mebendazole or albendazole; often curative
• Prognosis: late complication of papillary stenosis can be treated w endoscpic sphincterotomy

Question 62

Resection of colorectal liver mets

Answer 62

• consider laparoscopy pre-resection in high risk cases (eg v high CEA, indeterminate imaging for peritoneal disease)
• one-stage simultaneous multiple adequate hepatic resections, with preservation of adequate FLR = safe & effective if small & favourably positioned bilateral CRLM
• if extensive bilobar mets, strategies include
  
  • parenchymal-sparing hepatectomy (safe & effective w/o compromising onc outcomes & bc preserves parenchyma, increases potential for salvage repeat hepatectomy for pts w recurrent intrahepatic disease
  • combo of ablation w repeat PSH
  • two-stage hepatectomy if inadequate FLR
    
    • removal of portion of metastatic disease + occlusion of contralateral PV (by surgical ligation or subsequent perc embolisation); second curative-intent stage of operation done after hypertrophy of contralateral liver
    • long-term survival comparable to pts w more limited disease treated by single-stage
  • combo of multimodal therapies when complete resection of all mets not feasible
    
    • hepatectomy for main tumour mass
    • local tumour-ablative therapy to rest

Question 63

Risk factors for cholangiocarcinoma

Answer 63

• PSC/UC
• congenital cysts - choledochal cysts, Caroli disease
• APBD junction
• chronic biliary infection: eg typhoid carrier/parasite infestation (liver fluke - Asia)
• recurrent pyogenic cholangitis
• hepatolithiasis: 5-10% risk
• biliary-enteric anastomosis
• chemical carcinogens- eg nitrosamines, dioxin, asbestos, smoking
• viral hepatitis and cirrhosis

Question 64

Risk factors for gallbladder cancer

Answer 64

• Prevailing theory focuses on chronic inflammation w subsequent cellular proliferation
• Gallstones & chronic cholecystitis (0.5-3% those w stones), espec stones >3cm
• PSC (3%)
• Porcelain GB (2-3%)
• Choledochal cysts
• AJPBD
• Cholecystoenteric fistula
• Chronic infection – salmonella typhi carriage, Helicobacter colonization of biliary epithelium
• Carcinogen exposure - ­risk in workers in oil, paper, chemical, shoe, textile industries, also smokers
• Polyps >10mm (tend not to occur in pts w GS, chronic inflammation generally absent)
• obesity

Question 65

Risk of malignancy in GB polyps

Answer 65

• <5mm: ~20% decrease in size, ~5% disappear; some turn out to be stones
• polyps <1cm - 0-5% risk of malignancy
• polyps 1-1.5cm - ~10% risk of malignancy
• polyps >1.5cm - 46-70% risk of malignancy

Question 66

Staging for gallbladder cancer

Answer 66

Gallbladder does not have submucosa or muscularis mucosae

TX = primary tumour can’t be assessed

T0 = no evidence primary tumour

Tis = carcinoma in situ

T1 = invasion of lamina propria (T1a) or muscular layer (T1b)

T2 = invasion of perimuscular fibrous tissue on peritoneal side w/o involvement of serosa (T2a) or on liver side w/o extension into liver (T2b)

T3 = invasion of serosa/visceral peritoneum and/or directly invades liver and/or invades one adjacent structure/organ (eg extrahepatic bile duct, stomach, duo, colon, panc, omentum)

T4 = involvement of main portal vein or hepatic artery or invasion of ≥2 adjacent structures/organs

N1 = 1-3 nodes

N2 = ≥4 nodes

Stage 1 = T1

Stage 2a = T2aN0, Stage 2b = T2bN0

Stage 3 = T1-3,N0-1

Stage 4a = T4aN0-1, Stage 4b = T4b,anyN or anyT,N2 or M1

Question 67

Staging of HCC

Answer 67

• includes extent of disease & extent of cirrhosis work-up (mos tpts w HCC have 2 diseases & survival as much related to tumour as it is cirrhosis
• dx lap & lap USS = useful - lap USS better than preop staging CT
• TNM criticised as doesn’t accurately predict survival (doesn’t take liver function into account) & also relies on pathology that is frequently unavailable pre-op
  
  • but fibrosis score of underlying liver, AFP level, presence/absence of cirrhosis & MELD score = included as clinically significant prognostic factors
  • Okuda, Barcelona, CLIP systems more useful for predicting outcomes in pts w poor liver function who have advanced HCC & are undergoing nonsurgical therapy
    
    • CLIP (Italian): combines tumour-related features (macroscopic tumour morphology, serum AFP levels, presence/absence of portal vein thrombosis) + index of severity of cirrhosis to give prognostic score

these systems variably incorporate 4 features recognised as being important determinants of survival: severity of underlying liver disease, size of tumour, extension of tumour into adjacent strucutres, presence of mets +/- performance status

Question 68

Surgery for gallbladder cancer

Answer 68

• early (T1a)/incidental Ca which is limited to mucosa –> cholecystectomy alone
  
  • nodal disease <3%
• T1b and above - extended cholecystectomy and lymph node dissection
  
  • extended cholecystectomy = involves en bloc removal of GB with a rim of liver of at least 2cm adjacent to the gallbldder bed; a formal central liver resection (segments IVb and V) may be appropriate depending on location of tumour
    
    • when gross tumour extends into CBD, or a negative cystic duct margin can’t be obtained, extrahepatic bile duct resection should be done w Roux-en-Y hepaticojejunostomy
  • regional lymph node dissection = nodes in porta hepatis and along hepatoduodenal ligaments, including those of the cystic duct, common bile duct, hepatic artery and portal vein
• T1b - 15% nodes
• T2 - up to 50% nodes
• T3 - extended cholecystectomy en bloc w involved adjacent organ may be done but hasn’t been assoc w improved survival
  
  • in many cases need division of left hepatic duct and excision of biliary confluence + extended right hepatectomy
• T4 - generally locally unresectable due to vasc invasion of main PV or hepatic artery or involvement of multiple adjacent extrahepatic organs or structures, but curative resection may be possible in selected stage IVa disease
• consider adjuvant therapy for T4, positive LNs, R1 resection
• unresectable disease: 5FU based chemo or supportive care
• may include endoscopic orr perc biliary drainage, enteric stenting or intestinal bypass

Question 69

Surgery for hilar cholangio

Answer 69

• Bismuth I & II - en bloc resection of extrahepatic bile ducts & GB with 5-10mm bile duct margins and a regional lymphadenectomy with Roux-en-Y hepaticojejunostomy; resection of caudate lobe en bloc for hilar or intrahepatic cholangio now standard of care
  
  • clinically often difficult to distinguish between tyeps I and II and most recommend treating uncelar causes as type II
• Bismuth III&IV - in addition to above, usu requires hepatic lobectomy or trisectionectomy
  
  • may involve complex resection and recon of portal vein, hepatic artery or both

Criteria for unresectability:

• patient factors
  
  • medically unfit or otherwise unable to tolerate major operation
  • hepatic cirrhosis
• tumour factors
  
  • tumour extension to secondary biliary radicles bilaterally
  • encasement or occlusion of main portal vein prox to its bifurcation or bilat portal vein involvement
  • bilateral hepatic arterial involvement
  • atrophy of one hepatic lboe w contralateral portal vein branch encasement or occlusion
  • atrophy of one hepatic lobe w contralateral tumour extension to secondary biliary radicles
  • unilateral tumour extension to secondary biliary radicles w contralateral portal vein branch encasement or occlusion
  • need for portal vein resection not contraindication to resection but role of arterial resection & recon more controversial - signif increased M&M w/o long-term survival benefit
  • intraop frozen section should be done
    *

Question 70

The AJCC classifies all colorectal metastases beyond the local lymphatic basin as stage IV colorectal cancer.

Describe a classification system that expands on stage IV disease.

Answer 70

The European Colorectal Metastases Treatment Group have proposed a staging system for CRC liver metastases:

• IVa - easily resectable at detection
• IVb - borderline resectable at detection
• IVc - potentially resectable after NAC
• IVd - little or no hope of being rendered curable
• Va - resectable extra-hepatic disease
• Vb - unresectable extrahepatic disease

Question 71

Things that reduce the risk of post-ERCP pancreatitis

Answer 71

• wire-guided cannulation cf contrast-guided cannulation
• balloon dilatation of biliary sphincter is a risk but incidence can be reduced by longer duration of dilatation rather than shorter one
• prophylactic panc stent placement
• rectal NSAIDs
• aggressive periprocedure hydration with lactated Ringers - reduces incidence and severity

Question 72

Treatment options for HCC

Answer 72

• curative: transplant, resection, ablation
  
  • when underlying liver disease present, only transplantation is curative by simultaneously treating aetiology of HCC & preneoplastic lesions; recurrence virtually constant w all other treatments
• resection
  
  • in pts w/o cirrhosis, liver resection ideal
  • in pts w cirrhosis, mx depends on tumour extension, status of non-tumoural liver & general condition of pt
    
    • pts w CPC or CPC cirrhosis or portal HTN don’t tolerate resection
    • in pts w CPA, volume of FLR important: consider PVE
    • mx of underlying chronic liver disease reduces likelihood of recurrence
  • both anatomical resections (cf tumourecetomies) & wide (cf limited) margins may improve long-term survival w/o increasing risk - aim for >1-2cm margins to ensure potential satellite nodules/spread through microvasc invasion are also resected
  • lymphadenectomy recommended
  • adjuvant chemo not recommended
• transarterial - embolisation, chemoembolisation
  
  • TACE = 1 of 2 noncurative options that can improv survival
  • HCC receives almost 100% of blood supply from artery; obstruction of feeding vessel -> necrosis
  • can use iodised oil to target cytotoxic drugs - gets retained in malignant tumours
• ablative - ethanol injection- acetic acid injectoin- thermal ablation (cryotherapy, RFA, micrwave)
  
  • RFA most effective; initially done in pts unsuitable for resectional surgery; now for neoadj tx in liver transplant candidates & for tx of recurrence after liver resection
    
    • only likely to be successful for tumours <5cm & presence of >3 tumours is limitation
• systemic
  
  • chemotherapy - no role
  • hormonal ??
  • immunotherapy - Sorafenib (targets angiogenesis & EGF receptor pathways) - improves OS, first line if not eligible for resection, transplant, perc ablation or TACE, if still have preserved liver function
• radiotherapy
  
  • external beam limited value
  • radioembolisation comparable to chemoembolisation - inject radioisotopes directly into hepatic artery
• transplant
  
  • if partial liver resection precluded by anatomical factors or need to preserve sufficient FLR, or as a rescue treatment for intrahepatic tumour recurrence
  • most effective strategy to prevent HCC recurrence
  • criteria in cirrhosis pts:
    
    • if HCC confined to liver, no extrahepatic disease icnl LN, no vasc extension, limited tumour burden
    • initially Milan criteria: single tumour <5cm or presence of 2 or 3 tumours <3cm
    • now expanded UCSF criteria: single tumour <6.5cm or ≤3 tumours, largets <4.5cm w sum of tumour diameters <8cm

Question 73

Underlying liver function dominates prognosis in HCC, describe a scoring system that takes this into account (cf TNM)

Answer 73

CLIP combines tumor-related features (macroscopic tumor morphology, serum AFP levels, and the presence or absence of portal vein thrombosis) with an index of the severity of cirrhosis to determine a prognostic score ranging from 0 to 6

Question 74

Variations in cystic artery anatomy

Answer 74

• NORMAL: arises from RHA on right side of RHD in Calot’s and passes lateral to GB in 70% of cases
  
  • usu divides into ant and post branches; latter goes between GB & liver
• ABERRANT:
  
  • 20% arises from CHA, its bifurcation or from LHA
  • 10% from accessory RHA
  • 2.5% from GDA
  • also SMA
  • in 25% arises to left of duct system & usu crosses in front of ducts to reach GB
  • cystic artery can be v short with RHA in close proximity or even adherent to CD/HP
  • in 2-5%, artery divides early into multiple small branches and a significant cystic artery is never discovered

“may arise from common hepatic, proper hepatic, from left hepatic, from GDA or SMA and in either case may pass in front of cystic and bile ducts”

Question 75

Variations in cystic duct anatomy

Answer 75

• usu 2-8cm
• entry into CHD variable: angular 70%, parallel 20%, spiral 10% (ant or post)
• may have short CD, long CD or accessory CD
• 1-2% join RHD or RPSD
• may cross anomalous low-lying RHD in 1 in 1000

Question 76

What are the arguments for and against IOC?

Answer 76

For

• Increased recognition of CBD injury
• Helps identification of abnormal ductal anatomy
• If requisite skills for trans-cystic or CBD exploration are present then reduced number of procedures for patients with stones
• Allows for placement of a stent at time of IOC which improves success of subsequent IOC and relieves obstruction
• Detects previously unexpected CBD stones
• Keeps skills up/good for training

Against

• Occult CBD stone found in ~5%; many pass spontaneously so ~150 IOCs with 8 unnecessary CBD explorations done to clear 1 stone that would have caused symptoms (ie small unexpected stones likely clinically insignificant anyway)
• Doesn’t eliminate/reduce risk of CBD injury
• False positives expose patients to more risk
• Increased theatre time

Question 77

What are the causes of hepato-splenomegaly?

Answer 77

• Congestive
  
  • Cirrhosis
  • Heart failure
  • Venous thrombosis (Portal, Hepatic, IVC)
• Benign haematological
  
  • Haemolytic anaemias.
• Neoplastic
  
  • Myeloproliferative
  • ALL/CLL/AML/ALL
  • Polycythaemia rubra vera
  • Metastases
  • Primary splenic tumour
  • Multiple myeloma
• Infective
  
  • EBV, CMV
  • Parasitic; malaria, echinococcus
  • Abscesses; SBE, diverticular
  • Fungal
• Infiltrative
  
  • Gaucher’s disease
  • Amyloidosis
  • Niemann-Pick
  • Sarcoid
• Inflammatory
  
  • Lupus
  • Felty’s syndrome

Question 78

What are the components of a DeMeester Score?

Answer 78

The DeMeester score is derived from data collected during a 24-hour ambulatory pH study, often combined with impedance testing.

It generates a score from variables including:

• Total number of reflux events
• Longest episode of reflux
• Number of episodes of reflux greater than 5 minutes
• Time spent in reflux supine and standing

A normal value is <14.72

Question 79

What are the distinguishing features of common hepatic incidentallomas on CT and MRI?

Answer 79

• Haemangioma
  
  • Centripetal filling on arterial contrast
• FNH
  
  • Central feeding arteriole
  • Homogenous arterial enhancement with iso-enhancement of delayed phases
• Hepatic Adenoma
  
  • Blood and fat (heterogenous) components
  • Homogenous arterial enhancement with iso-enhancement of delayed phases
  • Young female on OCP
• HCC
  
  • Arterial enhancement with washout on later phases
  • Cirrhotic liver
  • DWI - restricts diffusion
• Cholangiocarcinoma
  
  • Heterogeneous minor peripheral enhancement with gradual centripetal enhancement
  • Often “absence of a mass” present; i.e IH duct dilatation without clear mass
  • DWI - restricts diffusion
• Metastases
  
  • Hypo-attenuating cannon-ball lesions
  • Most commonly gastrointestinal origin
  • Hyper-attenuating metastases from C.T.M.R.PnET tumours

Question 80

What are the functions of the liver

Answer 80

1. Fat metabolism
2. Carb/glucose metabolism
3. Protein metabolism and Nitrogen homeostasis
4. Immune function
5. Bile synthesis and secretion
6. Coagulation
7. Metabolism of drugs and toxins
8. Vitamin metabolism

Question 81

What are the indications for elective splenectomy?

Answer 81

• Haematologic disorders;
  
  • Hereditary anaemias
  • Primary hypersplenism
  • ITP
  • Autoimmune haemolytic anaemia
  • Selected cases of myelofibrosis, CLL, and lymphoma
• Primary splenic tumour
• Splenic abscess
• Splenic cysts
• Gastric varices due to splenic vein thrombosis
• Infilitrative diseases;
  
  • Gaucher’s and Niemann-Pick
  • Felty’s and Fanconi’s anaemia
  • Amyloidosis, sarcoidosis

Question 82

What are the microscopic consequences of splenectomy? (on blood film)

Answer 82

1. Howell-Jolly bodies (nuclear fragments)
2. Heinz bodies (Hb deposits)
3. Pappenheimer bodies (Fe deposits)
4. Target cells (increased surface membrane to cell volume ratio)
5. Siderocytes (iron not bound to Hb)
6. Acanthocytes
7. Transient leukocytosis
8. Transient thrombocytosis
9. Persistent lymphocytosis and monocytosis

Question 83

What are the pathological types of cholangiocarcinoma?

Answer 83

• 95% are adenocarcinoma (other histo variants 5%)
• 3 pathologic subtypes
  
  • sclerosing - tends to occur in prox bile ducts, causing periductal fibrosis in concentric pattern & circumferential duct occlusion
  • nodular - tends to occur in distal cholangios, firm mass based in duct wall, can be seen growing into duct lumen
  • papillary - tends to occur in distal cholangio, more common, polypoid lesion that is soft with less periductal fibrosis, though can grow to signif size often arise from well-defined stalk w bulk of tumour mobile within ductal lumen, more often resectable, better prognosis

Question 84

What are the two subdivisions of acute pancreatitis?

Answer 84

According to the Atlanta Classification:

• Interstitial oedematous pancreatitis - Acute inflammation of the pancreatic parenchyma and peripancreatic tissues, but without recognizable tissue necrosis
  
  • No findings of peripancreatic necrosis
  • Pancreatic parenchyma enhancement by intravenous contrast agent
• Necrotizing pancreatitis - Inflammation associated with pancreatic parenchymal necrosis and/or peripancreatic necrosis
  
  • Lack of pancreatic parenchymal enhancement by intravenous contrast agent, and/or
  • Presence of findings of peripancreatic necrosis

Question 85

What are “Worrisome and High risk Features” according to the Fukuoka Guidelines?

Answer 85

BE-CCALM-PT JEM

Worrisome

1. BD-IPMN >3cm
2. Enhancing mural nodule <5mm
3. CA19-9 elevated
4. Cyst growth >5mm in 3yrs
5. Abrupt cut-off of main duct w proximal atrophy
6. Lymphadenopathy
7. Main duct 5-9mm
8. Pancreatitis
9. Thickened and enhancing cyst wall

High-risk

1. Jaundice
2. Enhancing mural nodule >5mm
3. Main duct ≥10mm

Question 86

What can cause false positive Chromogranin A?

Answer 86

Liver or kidney failure, inflammatory bowel disease, atrophic gastritis or chronic use of proton-pump inhibitors

Question 87

What constitutes an unresectable Pancreatic Cancer?

Answer 87

Resectable

• localised to pancreas
• no evidence of SMV or portal vein involvement (ie no abutment, distortion, thrombus or encasement)
• preserved fat plane surrounding the SMA & celiac artery branches, incl the hepatic artery

Borderline

• solid tumour contact with SMV or PV of >180degrees or contact of ≤180degrees w contour irregularity of vein or thrombosis of vein, but suitable vessel prox & distal to site of involvement, allowing for safe & complete resection and vein reconstruction
• solid tumour contact w CHA (abutment or encasement) w/o extension to celiac axis or hepatic artery bifurcation allowing for safe & complete resection & recon
• solid tumour contact w SMA of ≤180 degrees

Unresectable

• mets including LN mets outside field of resection
• ascites
• solid tumour contact with SMA >180°
• solid tumour contact with Coeliac Axis >180°
• solid tumour contact with primary jejunal artery or vein
• un-reconstructable SMV/PV

Question 88

What do you take into consideration when dealing with a CBD stone during laparoscopic cholecystectomy?

Answer 88

1. General condition of the patient
2. Number, size and location of the stones
3. Anatomy of biliary tree – size of cystic duct & common duct (espec relative to size of stones) and whether contrast flows freely into duo
4. Size of the stone
5. Accessibility of the ducts

• Small stones (<4mm) may flush w Buscopan 20mg IV or Glucagon 1mg IV and saline
• Can place additional clip or endoloop on cystic duct, place large adjacent drain & subsequent ERCP
• Small stones are amenable to spiral basketing under a fluoroscopic approach
• Long or tortuous or inflamed cystic ducts will hamper a trans-cystic approach
• Medium stones (4-10mm) unlikely to be dealt w via fluoroscopy alone so use a trans-cystic 5mm scope; may need to dilate cystic duct up to 8mm
• Large stones (>10mm) should be treated w a trans-CBD approach, open if I am doing it
  
  • Alternatively, passing an antegrade transcystic stent through and post-op ERCP is a safe bail out

Question 89

What feature on CT imaging differentiates HCC from intra-hepatic cholangiocarcinoma?

Answer 89

The hallmark of HCC on CT and MRI is strong arterial enhancement and washout of contrast in the delayed phase, often with rim enhancement. Intra-hepatic cholangiocarcinoma shows delayed enhancement.

Question 90

What is chronic pancreatitis?

Answer 90

• Chronic pancreatitis is a fibro-inflammatory condition characterised by structural changes to pancreatic parenchyma which lead to endocrine and exocrine dysfunction
• The causes are varied;
  
  • Toxins
    
    • EtOH
    • Hyperclacaemia / Hyperlipidaemia
  • Idiopathic
  • Genetic
    
    • CFTR mutations (cystic fibrosis)
    • SPINK1 mutations
  • Autoimmune
    
    • In isolation
    • In conjunction with Sjögren’s, IBD, PBC
  • Recurrent acute pancreatitis
  • Obstructive causes
    
    • Pancreatic divisum
    • Sphincter of Oddi disorders
    • Stricture due to ERCP, stone disease.

Question 91

What is fibrolamellar carcinoma?

Answer 91

• rare variant of HCC w remarkably different clinical features
• occurs at 20-35yrs, generally w/o hx of cirrhosis, F:M
• path: usu well demarcated & encapsulated and may have cenral fibrotic ara; central scar can make it difficult to distinguish from FNH
  
  • doesn’t produce AFP but assoc w elevated neurotensin levels
  • LN invasion within hepatic pedicle frequent
• usu 8-10cm (large) at time of dx & symptomatic
• imaging: large solitary hypervascular heterogeneous liver mass w central hypodense region due to central necrosis or fibrosis, well defined margins, calcification in 68%
  
  • MRI - central scar has low attenuation on T2, whereas cenral scar of FNH has high attenuation
• management:
  
  • if resection considered, simultaneous lymphadenectomy recommended
  • if recurs, repeat surgery reasonable due to rel indolent disease course & relative inefficacy of non-surgical tx
  • transplant may be alternative option in select cases
• outcome: better than HCC, prob related to high-resectability rates, lack of chronic liver disease & more indolent course
  
  • long term survival in 50-75% but recurrence common ≥80%

Question 92

What is PSC?

Answer 92

• a rare idiopathic chronic disease, likely involving an autoimmune process, characterised by non-infective progressive obliterative fibrosis of the intra and extrahepatic bile ducts
• M>F, 20-50yrs
• 60-80% of cases occur in UC pts; PSC occurs in 5-11% of UC pts
  
  • routinely evaluate PSC pts for IBD but don’t routinely screen pts w IBD for PSC unless abnormal liver tests
  • less common associations: Crohn’s, Riedel’s thyroiditis, retroperitoneal fibrosis
• entire biliary tree affected by inflammation –> causes irregular partial obliteration of the duct lumen; intra- and/or extrahepatic ducts affected (most commonly both)
  
  • inflammation, fibrosis, cholestasis
  • progressive chronic cholestasis and advances at unpredictable rate to biliary cirrhosis & eventually death from liver failure
• complications:
  
  • ESLF
  • fat soluble vitamin deficiencies
  • metabolic bone disease espec osteoporosis
  • dominant biliary strictures
  • cholangitis & cholelithiasis (cholesterol and/or pigment stones)
  • cholangiocarcinoma 10-15% lifetime risk - often heralded by rapid clinical deterioration w jaundice, weight loss & abdo discomfort
    
    • dx can be v challenging in PSC - tests include biliary brush cytology, endobiliary biopsy, CT or MRCP and tumour markers
  • GB ca in 3-4%
  • NB 40-60% of GB polyps in pts w PSC are malignant
  • HCC (in pts w cirrhosis)
  • colon ca (in pts w concomitant UC)
• diagnostic approach
  
  • suspect if cholestatic liver tests espec if IBD
  • dx by cholangiographic evidence of characteristic bile duct changes (chain of lakes) & excluding secondary causes of sclerosing cholangitis, primary biliary cholangitis & IgG4-assoc cholangitis/autoimmune pancreatitis
  • liver biopsy may support dx but rarely diagnostic
  • antimitochondrial antibody - present in primary biliray cholangitis but not PSC
  • IgG4
  • exclude secondary causes of PSC: chronic bacterial cholangitis, infectious or ischaemic cholangiopathy, cholangiocarcinoma, choledocholithiasis, diffuse intrahepatic mets, eosinophilic cholangitis, intra-arterial chemo, mast cell cholangiopathy, portal hypertensive biliopathy, recurrent pancreatitis, recurrent pyogenic cholangitis, surgical biliary trauma
• ix:
  
  • pANCA positive in 30-80%
  • LFTs may fluctuate
  • cholangiogram w MRCP, ERCP or PTC or CT cholangio - beaded appearance or chain of lakes (long strictures concerning for cholangiocarcinoma)
    
    • benefit of MRCP = non-invasive & avoids introduction of bacteria
  • liver boipsy: pericholangitis, bile stasis, fibrous obliteration of small bile ducts w concentric replacement by connective tissue in ‘onion skin’ pattern
• mx
  
  • abx for cholangitis
  • cholestyramine for itch
  • no therapy that slows progression of disease
  • observation early in disease w mild sx reasonable
  • if symptomatic, ERCP/PTC/endoscopic therapies to stent/balloon dilate dominant strictures may help alleviate pruritis and reduce likelihood of cholangitis
  • exclude cholangiocarcinoma - may appear as dominant stricture; serum Ca19-9, brush cytology of biliary tree, endobiliary biopsy & FISH all used in assessment of dominant biliary stricture
  • perc or EUS-guided needle biopsies shouldn’t be done - precludes transplant
  • resection of extrahepatic biliary tree and HJ - may improve symptoms and postpone need for transplant
  • transplant superior to biliary surgical procedure - indicated for advanced disease w cirrhosis
  • cholecystectomy in PSC pts w GB polyps
• outlook
  
  • progression to cirrhosis after several years
  • median survival w/o liver transplant 10-12yrs
  • adenoCA espec in UC pts - in 10-30% - cholangio or GB
  • not affected by proctocolectomy
  • after liver transplant 80-90% 5yr survival
• surveillance
  
  • screen for fat soluble vitamin deficiencies (PR, vits A, D, E)
  • bone density exam at dx & q2-3yrs after
  • studies failed to show benefit of screening for cholangioca but given high incidence many screen annually & USS or MRCP + serum CA19-9
  • if PSC & cirrhosis, screen for HCC
  • if UC & PSC, colonoscopy screening

Question 93

What is small for size syndrome?

Answer 93

A constellation of symptoms and signs resulting from too small a ‘functional mass’ of liver for that individual recipient; leads to

• prolonged cholestasis (raised bili)
• coagulopathy (raised PT)
• portal HTN
• ascites
• GI bleeding
• death at 4-6wks from sepsis

Question 94

What is Sphincter of Oddi dysfunction?

What are the criteria to diagnose it?

Answer 94

• term SOD has been used to describe a clinical syndrome of biliary or pancreatic obstruction related to mechanical or functional abnormalities of the sphincter of Oddi. The literature regarding SOD is often difficult to interpret because of differences in nomenclature
• 2 separate pathologic entities are recognized based on their distinct pathogenic mechanisms: SO stenosis and SO dyskinesia; term SOD encompasses both
• has been assoc w 2 clinical syndromes: biliary SOD and idiopathic recurrent pancreatitis
• clinical criteria for FUNCTIONAL GB & SO disorders have been proposed on basis of expert consensus; Rome IV criteria specify 3 subsets of functional GB & SO disorders
  
  • functional GB disorder
  • functional biliary sphincter disorder
  • functional pancreatic sphincter disorder
• Rome IV criteria for biliary pain (need all of them)
  
  • Pain in epigastrium and/or RUQ
  • Episodes lasting ≥30mins
  • Recurrent sx occurring at diff intervals (not daily)
  • Pain builds up to steady level
  • Pain severe enough to interrupt daily activities or lead to ED visit
  • Pain not significantly (<20%) related to BM
  • Pain not significantly (<20%) relieved by postural change or acid suppression
  • Supportive criteria include: pain assoc w N&V, pain radiating to back and/or right infrascapular region, pain awakening pt from sleep
• Rome IV criteria for functional biliary SOD
  
  • Criteria for biliary pain fulfilled
  • Absence of bile duct stones or other structural abnormalities
  • Elevated liver enzymes (ALT, AST, bilirubin or ALP >2x normal that normalize between attacks) or dilated bile duct (>8mm) but not both (that would be more likely to be stenosis/type I)
• Rome IV criteria for functional pancreatic SOD
  
  • Documented recurrent episodes of pancreatitis (≥2)
  • Other aetiologies of pancreatitis excluded
  • Negative EUS
  • Abnormal sphincter manometry
  • (not part of Rome criteria but liver transaminases & bilirubin may also be elevated & may have dilation of panc duct)
• criteria for likely mechanical biliary SOD (type I): biliary-type pain AND abnormal LFTs AND duct dilatation (with bile duct stones/other structural abnormalities excluded)

Question 95

What is the criteria for biliary dyskinesia on HIDA scan

Answer 95

HIDA = radiolabelled iminodiacetic acid is given and will collect in GB; then pt given IV dose of CCK and %ejection of GB in response to CCK is calculated

EF 40% at 20mins after CCK or fatty meal administration in pts w/o stones = considered diagnostic of dyskinesia

cholecystectomy may be justifiable if typical biliary pain & absence of other disease processes - 50% likelihood of pain resolution

Question 96

What is the evidence base for ERCP in gallstone pancreatitis?

Answer 96

Theoretically, early ERCP in gallstone pancreatitis could remove impacted stones in the distal CBD, thereby alleviating the initiating stimulus and reducing pancreatic inflammation.

Three randomised trials assessing early ERCP have been published with mixed results. Overall there is a suggestion that early ERCP may be beneficial in patients with prognostically severe pancreatitis with evidence of cholangitis or obstructive pattern LFTs.

Question 97

What is the life cycle of echinococcus in humans?

Answer 97

1. Canine (dog/dingoe) hosts harbour adult Echinococcus granulosus tapeworms in their jejunum - definitive, asymptomatic host
2. Ova are passed in faeces; ingested by intermediate hosts; usually sheep.
   
   • (humans are inadvertant intermediate hosts)
3. In intermediate host, ova hatch to release larva due to interaction w bile salts & trypsin –> larva penetrate lamina propria in jejunum & are transported by portal system into liver (75%) or via lymphatics to lung
4. Larvae develop into hydatid cysts; mature cysts have 3 layers (cyst wall itself 2 layers)
   
   • innermost layer = endocyst - inner germinal layer which produces hydatid fluid, has absorbative function for nutrition & is where daughter cysts (endocysts) are formed
     
     • has brood capsules = small, intracystic cellular masses in which future worm heads evelop into scoleces (ie contain protoscolices)
     • in a definitive host, the scoleces develop into adult tapeworm, but in intermediate host can only differentiate into a new hydatid cyst
     • freed brood capsules & scoleces are found in the hydatid fluid & form the so-called hydatid sand
     • daughter cysts = true replicas of the mother cyst
   • exocyst = external, laminated, gelatinous acellular hilar membrane around germinal layer
   • ectocyst/pericyst = host-derived external fibrous capsule
5. Sheep offal is consumed by dogs (definitive host) so larvae re-infect the primary host
   
   • when a cyst-containing organ is ingested, the protoscolices evaginate then scolices attach to intestines of definitive host & develop into adult tapeworms which completes the lifecycle

Question 98

What is the life cycle of entamoeba histolytica in humans?

Answer 98

1. Ingested as cysts via the fecal to oral route
2. Incubation for 2-4 weeks (may be longer)
3. Excystation in the small bowel
4. Trophozoites colonize large bowel
5. Invade colon - amoebic dysentery
6. Invade porto-venous system - abscess

Question 99

What is the pathophysiology of choledochal cysts?

Answer 99

• Babbitt’s theory = based on an abnormal biliopancreatic junction, where the main ducts join abnormally proximal to the ampulla of Vater
  
  • Postulates that the long common channel allows mixing of the panc & biliary juices, which then activates pancreatic enzymes
  • These active enzymes cause inflammation & deterioration of the biliary duct wall, leading to dilation
  • Furthermore, greater pressures in the panc duct can further dilate weak-walled cysts
• Competing theories suggest choledochal cysts are purely congenital in nature, resulting from aganglionosis similar to Hirchsprung’s disease

Question 100

What is the pathophysiology of pancreatitis?

Answer 100

1. No matter what the inciting event, there is abnormal activation of proteolytic enzymes within the pancreatic acinar cell. There is abnormal co-localization of lysozymes and zymogen granules allowing cathepsin-B to hydrolyse trypsinogen.
2. Acinar cell injury allows trypsin to be released into the pancreatic parenchyma where it activates more trypsinogen. These overwhelm the natural anti-proteases.
3. Local inflammation causes monocytes and neutrophils to release cytokines including IL-1, IL-6, TNF, and PAF leading to SIRS.
4. Hypoperfusion and erosion into vessels leads to necrosis.

Question 101

What is the prognosis for patients with resectable colorectal liver metastases?

Answer 101

Patients with resectable colorectal hepatic metastases can look forward to a 5-year-survival of 40-50% and a 10 year survival of 24%, with age being no barrier to resection if fit.

Question 102

What is your framework when considering liver lesions?

Answer 102

Cysts

• Congenital
  
  • Simple cysts
  • Polycystic disorder
• Infective
  
  • Pyogenic or amoebic abscess
  • Hydatid cyst
• Neoplastic
  
  • Benign = Cystadenoma
  • Malignant
    
    • Cystadenocarcinoma
    • IPMN of bile duct
    • Primary liver ca with cyst degeneration
    • Cystic mets to liver - colorectal, neuroendocrine, GIST, SCC, breast
• Post-traumatic

Pseudotumours

• Foetal lobulatons or focal fatty sparing

Solid tumours

• Mesenchymal
  
  • benign - haemangioma, lipoma, angiolipoma
  • malignant - haemangiosarcoma
• Benign Epithelial
  
  • FNH
  • Hepatocellular adenoma
  • Bile duct adenoma/biliary hamartoma/von Meyenburg complexes
• Intermediate/benign epithelial
  
  • Dysplastic nodules
• Malignant Epithelial
  
  • Primary
    
    • Hepatoblastoma
    • HCC (incl fibrolamellar variant)
    • Cholangiocarcinoma
  • Secondary (mets)
  • Lymphoma

Question 103

Which organisms are asplenic patients susceptible to?

What immunisations should be given and when?

Answer 103

Bacteria with a polysacharide capsule are removed by the spleen, so loss of the spleen puts patients at increased risk of infection from; Pseudomonas, Strep. pneumoniae, Haemophilus influenzae, Neisseria meningitidis, E. coli, Salmonella, Klebsiella, group-B Streptococci, and Bordatella pertussis (Please SHiNE my SKiS and bordatella)

Deliver vaccines pre-operatively by at least two weeks where possible. 14 days post op following emergent splenectomy.

Hiberix, Pneumovax-23, Prevenar-13, Menactra, Influenza, DTaP.

Question 104

Worrisome imaging findings in someone with PSC

Answer 104

Progression of a stricture on serial cholangiograms

marked biliary dilation above a dominant stricture

polypoid ductal mass ≥1cm diameter

Question 105

Describe the metabolism of haemoglobin to stercobilin

Answer 105

• Stercobilin results from breakdown of the heme moiety of hemoglobin found in erythrocytes.
• Macrophages break down senescent erythrocytes and break the heme down into biliverdin (green pigment), which rapidly reduces to free bilirubin.
• Bilirubin binds tightly to plasma proteins (especially albumin) in the blood stream and is transported to the liver, where it is conjugated with one or two glucuronic acid residues into bilirubin diglucuronide, and secreted into the small intestine as bile.
• In the small intestine, some bilirubin glucuronide is converted back to bilirubin via bacterial enzymes in the terminal ileum. This bilirubin is further converted to colorless urobilinogen.
• Urobilinogen that remains in the colon can either be reduced to stercobilinogen and finally oxidized to stercobilin, or it can be directly reduced to stercobilin.
• Stercobilin is responsible for the brown color of human feces. Stercobilin is then excreted in the feces.