Tumor of the Round Ligament of the Liver with IgG4-Related Disease

Abstract

We report on the first case of a tumor of the round ligament of the liver in a patient with IgG4-related disease. The patient was a 75-year-old man who was undergoing regular evaluation for an intraductal papillary mucinous neoplasm. Follow-up CT showed a tumor (size 20 mm) in the falciform ligament of the liver. The pathological diagnosis was not confirmed with ultrasound-guided biopsy. The tumor enlarged slowly, and FDG-PET revealed mild uptake (SUVmax = 4.4). We suspected the tumor to be a leiomyosarcoma or mesenchymal neoplasm derived from the ligamentum falciforme and performed laparoscopic surgery. The tumor existed in the round ligament of the liver. We cut the G4 pedicle, which was in contact with the tumor, and resected the tumor including S4, which showed ischemia. A biopsy specimen from the round ligament of the liver showed infiltration of abundant IgG4-positive plasma cells with fibrosis. After surgery, elevated serum IgG4 levels were observed and IgG4-related disease was diagnosed.