Histo path - pancreas

Question 1

Pathophysiology of acute pancreatitis

Answer 1

Pancreas secretes typsinogen, which is converted to trypsin in the intestines. Think of this enzyme as the big digestive enzyme.

Within pancreas, enzymes are in vesicular form (zymogen) - are inactive.

Pancreatitis happens when these enzymes are erroneously activated, in particular trypsin. Auto digestion.

Usually from direct cell injury or obstruction.

Question 2

What is the difference between a periductal, perilobular and panlobular pancreatitis?

Answer 2

Periductal: If inflammation/insult is around pancreatic ducts - Due to necrosis of acinar cells near duct. Duct lies within the lobules so the origin is from in–> out

Perilobular: Necrosis at the edges of lobules 

    Usually due to poor blood supply, out --> in

Panlobular: both of the ↑ at the same time

Question 3

What are the distinctive cellular and histological signs of mild and severe pancreatitis?

Answer 3

Acute interstitial pancreatitis: mild, with edema and fat necrosis (yellow white foci) only (mild)

Histo: typically an acute inflammatory cell infiltrate and mixed with edema and fibrinous exudate

Acute necrotizing pancreatitis: more severe, may get hemorrhagic pancreatitis as well as fat necrosis (severe)

Histo: patchy necrosis typically in a periductal or perilobular distribution with a sparing of portions of the pancreas; diffuse interstitial edema due to microvascular leakage, fat necrosis, neutrophils, acinar and blood vessel destruction, interstitial hemorrhage

Question 4

Painful, localized, cystic collections of pancreatic secretions that develop after pancreatitis or trauma. Have no epithelial lining, fluid has a high amylase.

Answer 4

Pseudocyst

If infected, it becomes an abscess. Abscess will have immune cell infiltration.

Question 5

Pathophysiology of chronic pancreatitis

Answer 5

Chronic Inflammation with parenchymal fibrosis and loss of parenchymam, acinar cells cannot regenerate. Duct strictures with calcified stones and secondary dilatations

Variable pain and symptoms of pancreatic insufficiency (malabsorption, diabetes)

Caused by recurrent inflammation, most commonly alcohol (80%) or obstruction.

Question 6

Diagnosis of chronic pancreatitis

Answer 6

Clinical triad of steatorrhea, diabetes and pancreatic calcification on radiographic studies requires high degree of suspicion

Rx: Pancreatic duct drainage, Whipple resection (relieves pain in 50% of patients with pain)

Question 7

Chronic pancreatitis picture with hypercellular lymphoplasmacytic infiltrate

Answer 7

Autoimmune pancreatitis

Same mechanism as PSC

Large numbers of IgG4-Positive plasma cells 

Involves pancreas, bile ducts and other places 

Often called "IgG4 disease" 

Pancreas appears less fibrosed and ducts are more open.

Question 8

60 year old man - malignant tumour that secretes a lot of lipase. abdo pain, wt loss, nausea & diarrhoea.

Answer 8

Acinar Cell Carcinoma

Malignant epithelial neoplasm composed of cells with morphological resemblance to acinar cells and with evidence of pancreatic exocrine enzyme production

About
10% get multifocal fat necrosis and polyarthralgia due to lipase secretion.

May secrete AFP - patho for Acinar Cell Carc

Highly cellular with minimal stroma and no desmoplasia With eosinophilic granular cytoplasm. Positive immunoreactivity for lipase, trypsin and chymotrypsin.

Prognosis: median survival is 18 months from diagnosis. 5yr survival <10%

Question 9

60 year old man - Weight loss (cachexia) and anorexia

Upper abdominal and back pain (chronic, persistent and severe)

Answer 9

Ductal Adenocarcinoma

‘MUCIN secreting glands’

85% of all neoplasms in pancreas 

5% of cancer deaths (5th common) 

2:1 M:F ratio 

5-year survival is poor: 5% 

    Presents very late due to being retroperitoneal 

Head tumors: invades ampulla, obstructs bile flow, 50% have distention of biliary tree and progressive jaundice, 50% have pain, 85% have extension beyond pancreas at diagnosis

Question 10

Benign or potentially low grade malignant cystic epithelial neoplasm composed of cells which contain intracytoplasmic mucin. Always women.

Answer 10

Cystic tumour

Always women, mucin cysts. Low grade cancer or non-malignant

Question 11

Neuroendocrine tumours

Answer 11

Neuroendocrine tumours:  
"Salt and pepper nuclei"
        Often non-secretory 
       Contain neuroendocrine markers e.g. chromogranin 
        Behaviour unpredictable 
        Relate to MEN-1 syndrome 

Insulinomas: 

    Cancer of the Pancreatic Beta cell 
    Most common secretory cancer

Question 12

Cholecystitis

Gallstones, neutrophil infiltration

Answer 12

Acute

Question 13

Chronic inflammation, lymphocyte infiltration, fibrosis, Roitansky-Aschoff sinuses - diverticular crypts that push through muscle layer.

Answer 13

Chronic