Chapter 19 - Pancreas

Question 1

What is the most common pancreatic congenital anomaly? Key features

Answer 1

Pancreas division: failure of ventral and dorsal fetal duct systems to fuse
Bulk of pancreatic secretions to drain through smaller minor papilla; stenosis predisposes to chronic pancreatitis

Question 2

Annular pancreas

Answer 2

Congenital anomaly

Bandlike ring around second portion of duodenum -> duodenal obstruction

Question 3

Ectopic pancreas key features

Answer 3

Congenital anomaly
Common incidence
Sites: stomach, duodenum, jejunum, Meckel diverticulum and ileum
Submucosal
Mostly asymptomatic
Can cause inflammation, pain or rarely mucosal bleeding from ulcer

Question 4

Agenesis of the pancreas key features

Answer 4

Fatal if complete

Homozygous PDX1 gene (homeobox TF)

Question 5

Acute pancreatitis key features

Answer 5

Reversible parenchymal damage associated w damage
majority associated with biliary tract disease (gallstones0 or alcoholism
Enzymes digest parenchyma

Question 6

What are the most common mechanisms of acute pancreatitis?

Answer 6

Pancreatic duct obstruction: gallstones - females, older
Alcohol: direct toxic effect on pancreatic acinar cells and increases oxidative stress -> functional obstruction - male, younger age of onset
Cystic fibrosis: SPINK1 mutations and CFTR mutations -> protein plugging and duct obstruction

Question 7

Morphology of acute pancreatitis

Answer 7

Mild interstitial edema and inflammation to extensive necrosis and hemorrhage
Acute necrotizing pancreatitis - gray-white parenchymal necrosis and chalky white fat necrosis
Hemorrhagic: patchy red-black hemorrhage w fat necrosis

Question 8

Clinical features of acute pancreatitis

Answer 8

Abdominal pain, nausea, anorexia
Elevated plasma lvls of pancreatic enzymes
Full-blown = medical emergency: intense abd pain, peripheral vascular collapse and shock from explosive activation of systemic inflammatory response
Death from: shock, ARDS, acute renal failure
Lab: marked serum amylase and lipase elevations
Hypocalcemia -> calcium soaps in fat necrosis

Question 9

Treatment of acute pancreatitis

What are the possible sequalae?

Answer 9

Restrict oral intake - rest pancreas
Analgesia, nutrition, and volume support
Sequelae: sterile pancreatic abscesses and pancreatic pseudocysts

Question 10

What are the features of chronic pancreatitis?

Answer 10

Inflammation with irreversible parenchymal destruction and fibrosis
Late stages: endocrine or exocrine parenchyma is destroyed -> malabsorption, DM, pseudocysts
Middle aged male
Long-term alcohol abuse most common
Most pts w recurrent bouts of acute pancreatitis develop chronic pancreatitis
Prognosis: long-term poor

Question 11

What do repeated episodes of acinar cell injury induce in chronic pancreatitis?

Answer 11

profibrogenic cytokines - TGF-B and PDGF
Drive myofibroblast proliferation, colalagen secretion and ECM remodeling -> irreversible fibrosis -> pancreatic insufficiency

Question 12

What is the MOST COMMON cyst of the pancreas?

Answer 12

Pseudocysts

Question 13

What are pseudocysts?

Answer 13

Collection of necrotic, hemorrhagic material rick in pancreatic enzymes
75% of pancreatic cysts
Cysts NOT lined by epithelium
Encircled by fibrosis granulation tissue
Occur after bouts of acute pancreatitis or following trauma
Many spontaneously resolve
Can compress gallbladder ducts

Question 14

What is pancreatic carcinoma ?

Answer 14

Infiltrating ductal adenocarcinoma

Most aggressive of solid malignancies

Question 15

What are the precursors to pancreatic cancer?

Answer 15

Non-neoplastic epithelium-> small ductal noninvasive lesions-> invasive carcinoma
Lesions are called pancreatic intraepithelial neoplasms (PanINs)

Question 16

What is the pathogenesis of pancreatic cancer?

Answer 16

KRAS (chr 12) - MC altered oncogene
CDKN2A/p16 (Chr 9) - MC tumor suppressor gene (hypermethylation)
SMAD4 (Chr 18) - second most common tumor suppressor gene; important bc this mutation is rare in other cancers (important for TGF-B receptor signal transduction)

Question 17

What is the epidemiology and inheritance of pancreatic cancer?

Answer 17

80% are 60-80
MC in blacks
Smoking increases risk 2x
Modestly increase risk: Chronic pancreatitis, consumption of diet rick in fats, FH of pancreatic cancer, germline mutations in CDKN2A, and DM

Question 18

What is the morphology of pancreatic cancer

Answer 18

Most arise in head of gland
Highly invasive
Obstruct distal common bile duct -> jaundice
Dense desmoplastic reaction

Question 19

What are the clinical features of pancreatic cancer?

Answer 19

WL and pain typical presenting sx
Jaundice
Courvoisier’s sign: jaundice, palpable gallbladder
Metastases common
Most unresectable at presentation
Poor prognosis
Migratory thrombophlebitis - Trousseau syndrome, can occur with pancreatic neoplasms as well as other adenocarcinomas