A 70-year-old woman with an increased uptake of 18-Fluorodeoxyglucose (FDG) in whole liver on positron emission tomography (PET) was referred to our hospital. Laboratory examinations showed increased serum levels of total immunoglobulin G (IgG) and IgG4. Gallium scintigraphy showed a remarkable uptake in the liver but not in any other organs. On computed tomography (CT) and magnetic resonance imaging (MRI), multiple foci of abnormal density were observed in the liver, but the pancreas and bile duct lacked any indications of IgG4-related sclerosing disease. A liver biopsy specimen revealed multiple non-necrotizing granulomas. This is the first report of hepatic sarocidosis in a patient with an elevated serum level of IgG4.