Gallbladder

The gallbladder, in pathology (and general surgery), is a growth industry... due to the worsening obesity epidemic.

Normal

Histology

• NO muscularis mucosae.
• Small amount of lymphocytes in the lamina propria.

Pathology

Most common:

• Cholelithiasis with cholecystitis.

Cholecystitis

Epidemiology

• Female, fat, fertile, family history, forty (though now getting younger... as people get fatter).

Etiology

• Cholelithiasis.
• Thick bile (acalculous cholecystitis).

Clinical (classic)

• Constant right upper quadrant pain after a fatty meal.
• Positive Murphy's sign (physical exam, with ultrasound).

Gross

• Strawberry-like appearance - common (due to cholesterolosis -- see below)
  • Small ridges (microvillus architecture).
    • Normal gallbladder mucosa = smooth.
• Congestion/erythema.

Microscopic

• Rokitansky-Aschoff sinuses
  • Entrapped epithelial crypts -- pockets of epithelium in the wall of the gallbladder.
• +/-Foamy macrophages in the lamina propria.
• Inflammatory cells.
  • Neutrophils are not essential for the Dx - usually secondary to necrosis/ulceration or infection.

Cholesterolosis

General

• Common in cholecystitis.
• Associated with yellow gallstones (cholesterol type gallstones).

Gross

Features:

• Mucsoa has strawberry-like appearance.

Microscopic

Features:

• Foamy macrophages.

Image:

• Cholesterolosis (WC).
• Cholesterolosis (WC).

Cholelithiasis

• Often accompanies cholecystitis/contributes and/or causes cholecystitis

The two types of gallstones:

• Cholesterol stones
  • More common than pigment stone.
  • Appearance:
    • Clear or yellow.
    • Opaque or translucent.
    • Sometimes shinny.
• Pigment stones
  • Due to high RBC turnover, e.g. sickle cell anemia, thalassemia.
  • Appearance:
    • Black - key feature.
    • Dull.

Note: Most stones are a mix technically speaking, i.e. cholesterol and pigment. Many call yellow stones that are often a mix "cholesterol stones".

Crystalline gallstones -- UC association (?):

Adenomyosis

General

• Glands in muscle.
• Analogous to what happens in the uterus.
• Significance??? -- consequence of long standing cholecystitis/Rokitansky-Aschoff sinuses???

Histology

• Glands in muscularis propria of the gallbladder wall.

Gangrenous gallbladder

• Necrosis of gallbladder wall (muscularis propria).

Polyps

• Polyps - significant as they may be adenomatous, i.e. pre-cancerous.

Flat dysplasia:

• Nuclear changes.
  • Incr. NC ratio.
  • Hyperchromasia (essential).
  • +/-Intestinal metaplasia --> goblet cells.

Premalignant lesions - metaplasia/dysplasia

• Metaplasia assoc. with carcinoma.

Hypothesis:

• Antral type metaplasia --> intestinal metaplasia --> dysplasia --> carcinoma.

Intestinal metaplasia

Definition:

• Presence of goblet cells -/+ paneth cells.

Significance:

• Increased risk of carcinoma.

Antral type metaplasia

General

• AKA pyloric metaplasia, pseudopyloric metaplasia, mucous gland metaplasia.

Microscopic

Features:

• Cells with...
  • Abundant, pale, apical mucin.
  • Small basal nucleus.
• Cells often in nests -- below luminal surface.
• Cells vaguely resemble foveollar epithelium of the stomach.

Dysplasia

• Premalignant lesion.

Microscopic

Features:

• Nuclear crowding.
• Nuclear hyperchromasia.

Notes:

• Like in the colon.

Carcinoma

Epidemiology

• Associated with gallstones.
• Sex: female > male.
• Location: usually fundus, sometimes body.

Notes:

• Calcification of gallbladder wall aka "Porcelain gallbladder" -- not associated with carcinoma.
• Cholangiocarcinoma is dealt with in the liver neoplasms article.

Microscopic

• Usually adenocarcinoma.
  • Mimics appearance of pancreatic ductal adenocarcinoma-- but less cellular mucin.

Notes:

• May be very subtle, i.e. difficult to differentiate from normal glands.

See also

• Liver.
• Gastrointestinal pathology.