Xanthogranulomatous cholecystitis is an uncommon inflammatory disease of the gallbladder which may be difficult to differentiate from malignancy, both on imaging and pathologically. It is characterized by presence of multiple intramural nodules.
It is seen predominantly in female patients at 60-80 years of age.
The macroscopic appearance is of a poorly defined, nodular yellow mass that infiltrates the wall of the gallbladder. There is gallbladder wall thickening, and the process may infiltrate directly into the adjacent soft tissues, liver, duodenum or colon 1.
Histologically, it consists of a mixture of ceroid (wax-like) xanthogranuloma with foamy histiocytes, multinucleated foreign body giant cells, lymphocytes and fibroblasts containing areas of necrosis.
It is postulated that xanthogranulomatous cholecystitis results from rupture of occluded Rokitansky-Aschoff sinuses, with subsequent intramural extravasation of inspissated bile and mucin 3. This further attracts histiocytes to phagocytize the insoluble cholesterol.
Spectrum of pathological findings includes 4,5:
- thickened gallbladder wall: ~90% diffuse and ~10% focal
- infiltration of pericholecystic fat: in 45% focal, in 54% diffuse
- hepatic extension: ~45 %
- biliary obstruction: ~36%
- lymphadenopathy: ~36 %
- a relationship with gallbladder carcinoma is uncertain 6,7
- gallbladder wall thickening may be diffuse or focal
- intramural hypoechoic nodules or bands
- if the inflammatory process has infiltrated the adjacent liver, there may be loss of the intervening fat plane, with focal hypoechogenicity of hepatic parenchyma
- gallstones often present
- 5-20 mm small intramural hypoattenuating nodules
- poor/heterogeneous contrast enhancement
- features of local infiltration, or other complications, such as perforation, abscess formation or formation of fistulous tracts 1
Treatment and prognosis
Because of its imaging similarity to gallbladder carcinoma, cholecystectomy is often performed. Fine needle aspiration has been performed to differentiate the two entities.