IgG4-related cholecystitis misinterpreted as gallbladder cancer, a case report

INTRODUCTION: Immunoglobulin G4-related disease (IgG4-RD) is a new defined entity with features that factually have been overlapped with other diseases with distinctly diverse treatments and prognoses. CASE PRESENTATION: This report describes a 50-year-old woman who presented with abdominal pain from 3 months ago. The patient underwent open cholecystectomy with Roux-en-Y hepaticojejunostomy due to suspicious of malignancy. The histological examinations revealed acute on chronic cholecystitis with extensive fibrosis and many inflammatory cells infiltration composed of plasmacells and eosinophils without any evidence of malignancy. Pathological and immunohistochemical examination for IgG4 compatible with IgG4-RD. So, pathological assessment is essential for the diagnosis. CONCLUSION: IgG4-RD in gastrointestinal tract frequently misinterpret as malignancy before surgery, and surgeon should notice this disease in the differential diagnosis in order to choose the treatment.