Immunoglobulin G4-related Disease Presenting as an Intraperitoneal Mass

Abstract

A 63-year-old woman had been examined at another hospital for the investigation of upper abdominal discomfort, loss of appetite, and nausea beginning two years earlier. These investigations found two swellings, a mass on the anterior surface of the spleen and an intrapelvic mass, and she was referred to our hospital for diagnosis and treatment. Upper and lower gastrointestinal endoscopies and endoscopic ultrasound showed that these were extramural lesions, and lymph node swelling was suspected. Aspiration cytology did not result in a diagnosis, and it was decided to carry out surgical lymph node biopsy for suspected Castleman's disease. The patient had previously undergone numerous surgical procedures, and adhesions were present in the peritoneal cavity, but numerous white nodules that adhered strongly to the surrounding tissues were also present, exhibiting the appearance of disseminated lesions. However, intraoperative rapid pathology found no signs of malignancy. At the target lymph node, penetrative invasion of the diaphragm had occurred. Pathological testing showed tissue infiltration by immunoglobulin G4 (IgG4)-positive plasma cells, storiform fibrosis, and obstructive phlebitis, leading to a diagnosis of IgG4-related disease. Once diagnosed, the patient was started on steroids in the Department of Immunology and Oncology. A case of difficult-to-diagnose IgG4-related disease is reported.