Description
Xanthogranulomatous cholecystitis (XGC) is an uncommon variant of chronic cholecystitis characterised by focal or diffuse destructive inflammatory process of the gallbladder. It’s marked by severe fibrosis, thickening of the gallbladder wall, and a pronounced macrophage response that often extends into adjacent structures.
Pathogenesis
The exact pathogenesis of XGC remains uncertain, but it is believed to be a sequela of longstanding cholelithiasis and chronic inflammation. The process is marked by intramural accumulation of lipid-laden macrophages (foam cells), chronic inflammatory cells, multinucleated giant cells, and areas of necrosis and fibrosis.
Epidemiology, Risk Factors & Associations
- XGC accounts for approximately 1-10% of cholecystitis cases.
- There is a female predilection, with a female to male ratio of approximately 3:1.
- The median age at diagnosis is around 65 years.
- Key risk factors include cholelithiasis and chronic gallbladder inflammation.
Clinical Features
- Patients often present with symptoms of chronic cholecystitis, including right upper quadrant pain, fever, nausea, and vomiting.
- The physical examination may reveal a palpable, tender mass in the right upper quadrant due to the gallbladder wall thickening.
- Jaundice may occur but is less common.
Complications
Potential complications of XGC include:
- Formation of gallbladder adhesions to adjacent organs.
- Formation of fistulas, including cholecystoenteric fistulas.
- Increased risk of gallbladder carcinoma.
Subtypes
There are no specific subtypes of XGC. The condition is usually categorised based on the extent of disease (focal or diffuse).
Pathological Features
Morphology
- The gallbladder wall is typically thickened and firm, sometimes with a nodular surface.
- The mucosa may show patchy erythema or ulceration.
- Histopathological examination is necessary for diagnosis.
Histopathology
- Lipid-laden macrophages (foam cells), chronic inflammatory cells, and multinucleated giant cells are present in the lamina propria and submucosa.
- Necrosis, fibrosis, and occasional abscess formation may be seen.
- The condition may extend to the serosal surface and into the liver.
Biochemistry/Genetics
- No specific biochemical or genetic alterations have been identified in XGC.
Radiological Features
CT
- Wall thickening of the gallbladder with high-attenuation areas corresponding to the accumulation of lipid-laden macrophages.
- May show enhancement with contrast, often heterogeneous.
- Intramural hypoattenuating nodules are suggestive of XGC.
- Extension into liver or other adjacent structures may be visible.
MRI
- T2-weighted imaging may show high-intensity nodules in the gallbladder wall.
- Diffuse or focal gallbladder wall thickening.
- Post-contrast images show enhancement, often heterogeneous.
Ultrasonography
- Gallbladder wall thickening is frequently observed, often with a stratified pattern.
- The presence of intramural hypoechoic nodules may suggest XGC.
Grading and Staging
There is no specific grading or staging system for XGC. The severity of the disease is usually described based on the degree of gallbladder wall thickening and extent of inflammation.
Differential Diagnosis
Key differential diagnoses for XGC include:
- Gallbladder carcinoma: The extensive wall thickening in XGC can mimic carcinoma. The presence of intramural hypoattenuating nodules on CT or high-intensity nodules on T2-weighted MRI may help distinguish XGC.
- Chronic cholecystitis: Chronic inflammation of the gallbladder can cause wall thickening that mimics XGC. However, the severe fibrosis and macrophage response seen in XGC are typically not present in routine chronic cholecystitis.
- Acute cholecystitis: XGC can be differentiated from acute cholecystitis based on the chronic symptoms and radiological findings such as the presence of intramural nodules.
Management
- Patients with suspected or confirmed XGC are usually referred to a surgeon for consideration of cholecystectomy.
- Given the risk of adhesions and invasion into adjacent structures, these surgeries can be challenging and may require an open approach.
- Preoperative diagnosis is essential to adequately prepare for these complexities.
- Percutaneous biopsy can be performed, but the definitive diagnosis is typically made on histopathology post-cholecystectomy.
- Intraoperative frozen section assessment may be utilised to exclude gallbladder carcinoma.