IgG4 disease: The great masquerader.

Systemic IgG4 disease can have a wide spectrum of clinical presentation, which can mimic several other disease entities. In this report, we describe a series of two patients with IgG4-related disease who were referred to us initially with the diagnosis of acute cholecystitis and the second patient with metastatic pancreatic adenocarcinoma with peritoneal metastasis respectively.