IgG4-Related Sclerosing Cholecystitis Mimicking Locally Advanced Gallbladder Carcinoma: A Case Report

Abstract

Background: Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder that can involve multiple organs. Gallbladder involvement is uncommon and may closely resemble gallbladder carcinoma, particularly when it produces focal wall thickening, a mass-like lesion, or apparent invasion of adjacent organs.

Case presentation: A 60-year-old man presented with malaise, anorexia, weight loss, and intermittent abdominal pain for three months. Contrast-enhanced computed tomography (CECT), ^18Ffluorodeoxyglucose positron emission tomography (FDG-PET), and magnetic resonance cholangiopancreatography (MRCP) demonstrated an irregular infiltrative lesion involving the gallbladder wall, with suspected extension into the adjacent liver and transverse colon. A diagnosis of locally advanced gallbladder malignancy was therefore considered. The patient underwent radical cholecystectomy with wedge resection of the adjacent liver, right hemicolectomy, and regional lymph node dissection. Gross examination revealed an irregular, firm, grey-white lesion involving full-thickness of the gallbladder wall with focal extension into the adjacent liver and adherent transverse colon. Histological examination demonstrated dense transmural lymphoplasmacytic inflammation, prominent fibrosis with focal indistinct storiform architecture. The inflammatory and fibrotic process extended into the adjacent hepatic parenchyma and colonic muscularis propria. No malignant epithelial proliferation was identified. Immunohistochemistry demonstrated approximately 25 IgG4-positive plasma cells per high-power field.

Conclusion: The combination of characteristic lymphoplasmacytic inflammation, storiform-pattern fibrosis, tissue extension, and increased IgG4-positive plasma cells supported a diagnosis of probable IgG4-related sclerosing cholecystitis. This case emphasizes that IgG4-related cholecystitis should be considered in the differential diagnosis of mass-forming or infiltrative gallbladder lesions, particularly when imaging suggests locally advanced malignancy. Recognition of this entity is clinically important because IgG4-RD may respond well to corticosteroid therapy and, in appropriately selected patients, early recognition may prevent unnecessarily extensive surgery.