Xanthogranulomatous cholecystitis

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 characterised by presence of multiple intramural nodules.

Epidemiology

It is seen predominantly in female patients in their seventh or eighth decades.

Clinical presentation

Patients typically present with symptoms and signs similar to cholecystitis including right upper quadrant pain with a positive Murphy's sign. Leukocytosis is generally present.

Pathology

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 ^{ref needed}:

• 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 %

Associations

• gallbladder carcinoma: 11% ^{ref needed}

Radiographic features

Ultrasound

• gallbladder wall thickening may be diffuse or focal
• intramural hypo-echoic nodules or bands
• if the inflammatory process has infiltrated the adjacent liver, there may be loss of the intervening fat plane, with focal hypo-attenuation of hepatic parenchyma
• gallstones often present

CT

• 5-20 mm small intra-mural hypo-attenuating nodules
• poor/heterogeneous contrast enhancement
• features of local infiltration, or other complications, such as perforation, abscess formation or formation of fistulous tracts ¹

Differential diagnosis

• gallbladder carcinoma  may be indistinguishable; the presence of hypoattenuating nodules within the thickened gallbladder wall favours xanthogranulomatous cholecystitis
• acute cholecystitis.