Pancreatic and Biliary Pathology

Pancreatic and Biliary Pathology

• Gallbladder anatomy and histology:
  • Pear-shaped sac, stores bile
  • Attached to the liver and duodenum by connective tissue
  • Composed of mucosa, muscularis propria, and serosa
  • Surface epithelium: tall columnar cells
• Cholestérolisis:
  • Asymptomatic condition due to cholesterol ester and triglyceride accumulation in subepithelial macrophages of the gallbladder.
  • Yellow, flat deposits on the gallbladder mucosa.
  • May exhibit a speckled appearance ("strawberry gallbladder").
  • Microscopic findings: foamy macrophages in the lamina propria and epithelium
• Cholesterol Polyp:
  • Most common benign polyp (50-90%)
  • Typically found in women between 40 and 50 years of age.
  • 4 to 15 mm, yellow, soft, and often pedunculated.
  • Microscopic: Macrophages loaded with lipids, lined by normal gallbladder epithelium.
• Acute Cholecystitis:
  • Inflammation of the gallbladder, sometimes associated with gallstones.
  • Enlarged, distended gallbladder.
  • Congested and inflamed blood vessels.
  • Thickened gallbladder wall with edema and hemorrhage.
  • Ulcers with blood clot, pus and bile.
  • Microscopic: Edema, congestion, hemorrhage, fibrin deposition around the muscular layer and later necrosis, neutrophils in the mucosa.
• Chronic Cholecystitis:
  • Persistent inflammation of the gallbladder.
  • Often associated with gallstones, obstructing the cystic duct, causing intermittent pain.
  • Microscopic: Mild chronic inflammation, Rokitansky-Aschoff sinuses, granulomas, and smooth muscle hypertrophy.
  • Rokitansky-Aschoff sinuses are tubular structures in the gallbladder wall associated with increased intraluminal pressure
• Gallbladder Carcinoma:
  • Rare cancer of the gallbladder.
  • 75% affect women, typically developing after 72 years of age
  • Most are adenocarcinomas.
  • Often presents with diffuse wall thickening and/or papillary or exophytic tumors.
  • Microscopic: Infiltrative (diffuse thickening and induration) or exophytic architectural patterns; formation of glands, and typical high-grade characteristics.
• Pancreas Anatomy:
  • 15 cm long, 60-140 grams
  • J-shaped, loop around the duodenum
  • Divided into head, body, and tail
  • Retroperitoneal organ
  • Touches aorta, splenic vein, and left kidney.
• Pancreas Histology:
  • Exocrine pancreas: acinar cells, intercalated and intralobular ducts, blood vessels.
  • Endocrine pancreas: Islets of Langerhans (alpha, beta, delta cells) and other cells.
• Annular Pancreas
  • Rare developmental abnormality.
  • Head of the pancreas encircles the duodenum
  • Can constrict the duodenum lumen.
  • Often associated with Down syndrome and other congenital disorders
• Pancreas Divisum:
  • Most common congenital anomaly of the pancreas
  • Failure of the ventral and dorsal pancreatic ducts to fuse
  • Separate pancreatic duct systems feeding into two duodenal papillae
  • May increase risk for pancreatitis
• Acute Pancreatitis:
  • Inflammation and edema of the pancreas.
  • Severe pain radiating to the back, nausea, vomiting, fever, and chills can occur.
  • Symptoms and signs can include: severe epigastric pain radiating to the back, nausea, vomiting, diarrhea, fever/chills, and hemodynamic instability.
  • Signs: Cullen's sign (hemorrhage around the umbilicus) and Grey Turner's sign (hemorrhage in the flank)
• Pathogenesis of Acute Pancreatitis
  • Duct Obstruction leading to edema, compression, ischemia, and acinar cell injury
  • Release of pancreatic and lysosomal enzymes, activation, and auto-digestion
  • Defective intracellular transport of proenzymes within acinar cells
• Gross and Microscopic description of Acute Pancreatitis:
  • Swollen, indurated, edematous, hemorrhagic, or necrotic.
  • Yellow nodules of fat necrosis in the pancreas, mesentery, and peritoneal fat
• Chronic Pancreatitis:
  • Repeated attacks of inflammation resulting in fibrosis.
  • Hard, shrunken pancreas, dilated ducts, calcified concretions, and potentially pseudocysts.
• Gross and Microscopic description of Chronic Pancreatitis:
  • Hard, shrunken, dilated ducts.
  • Visible calcified concretions, (plugs) and pseudocysts.
  • Loss of acini and ductal tissue, but islets spared, irregularly distributed fibrosis.
  • Dilated ducts with concretions, and Chronic inflammation around lobules and ducts.
• Exocrine Pancreatic Tumors: Ductal Adenocarcinoma:
  • Infiltrative glandular neoplasm that develops from pancreatic ductal epithelium.
  • Poor prognosis (5-year survival rate 6%).
  • Typically diagnosed in head, body, or tail of pancreas.
  • Commonly associated with upper abdominal symptoms such as jaundice, abdominal distention, and weight loss.
• Acinar Cell Carcinoma:
  • Malignant epithelial neoplasm with cells resembling acinar cells
  • Highly cellular with minimal stroma; solid, nesting, glandlike pattern.
• Neuroendocrine Neoplasms
  • Rare tumors originating from neuroendocrine cells of the pancreas.
  • Can be well differentiated or poorly differentiated carcinomas.
  • Markers can be elevated like chromogranin A, CD56 and synaptophysin, and tumors can cause hormone imbalances.

This quiz covers essential aspects of pancreatic and biliary pathology, focusing on gallbladder anatomy, histology, and various conditions such as cholesterolisis and acute cholecystitis. Test your knowledge on the microscopic findings and clinical significance of these conditions.