Immunoglobulin G4-related disease mimicking gallbladder cancer with associated choledochal cyst: A case report of a malignant masquerade

Abstract

Immunoglobulin G4 (IgG4)-related disease is a recently described autoimmune disease that can involve diverse organ systems, causing pancreatitis, cholangitis, retroperitoneal fibrosis, and thyroiditis to name a few. Key histological features include storiform fibrosis, obliterative venulitis, and intense inflammatory infiltrate composed of lymphoplasmacytic cells. The disease has a tendency to present with mass-forming lesions, often difficult to differentiate from malignant processes. We report the case of a 48-year-old male from an area endemic for gallbladder cancer (north India). He presented with a short history of abdominal pain and was found to have asymmetric thickening of the gallbladder wall with a soft-tissue mass invading the adjacent liver. In addition, the bile duct was dilated throughout its extent. A clinical and radiological diagnosis of gallbladder cancer with choledochal cyst was made, and the patient underwent radical cholecystectomy with bile duct excision. Histopathology surprisingly demonstrated IgG4-related disease with no evidence of malignancy. Notably, serum levels of immunoglobulins were found to be normal. Preoperative diagnosis was challenging due to the absence of other manifestations. IgG4-related disease is a possible diagnostic pitfall and should be included as a possible differential diagnosis for gallbladder masses.

Keywords: autoimmune disease; case report; cholecystitis; gallbladder mass; immunoglobulin4‐related sclerosing disease.

Figure 1

(a) CECT scan of the abdomen with axial sections showing eccentric gallbladder wall thickening with low‐density soft‐tissue lesion (arrow) infiltrating the liver parenchyma (arrowhead). (b) Contrast‐enhanced computed tomography scan of the abdomen with axial sections showing eccentric gallbladder wall thickening with a soft‐tissue mass lesion with central hypodensity (arrow). (c) Magnetic resonance cholangiopancreatogram showing a diffusely dilated common bile duct with distal tapering. The main pancreatic duct appears normal. (d) Gross specimen of extended cholecystectomy showing the gallbladder (cut open) with a thickened wall (arrow). A hard mass was present in the fundus; however, the overlying mucosa was normal. (e) Microscopic view of the gallbladder wall showing storiform, transmural fibrosis, and intense mononuclear inflammatory infiltrate (HE stain, ×100). (f) Microscopic view of the gallbladder wall showing abundant immunoglobulin G4+ (IgG4+) plasma cells (immunohistochemistry of IgG4, ×400).