A Case of Extramedullary Plasmacytoma Preoperatively Diagnosed as GIST of the Stomach with a Suspicious Origin in the Perigastric Lymph Nodes

Abstract

An asymptomatic 67-year-old woman was incidentally detected to have a 7-cm tumor on the greater curvature side of the stomach by a CT scan. Following close examination, gastrointestinal stromal tumor (GIST) of the stomach was suspected and partial gastric resection was performed. The histopathological diagnosis was extramedullary plasmacytoma, and there was no continuity between the lesion and the stomach. Additional examination confirmed there were no distant metastases. She was decided to be followed without treatment under the diagnosis of extramedullary plasmacytoma. She is doing well without recurrence as of 2 years and 3 months after the operation.

Extramedullary plasmacytoma is a type of plasma cell tumors. Only 5 cases of the disease arisen in the intraperitoneal lymph node, including our case, have been reported in Japan, except for those arisen in the retroperitoneum. We report a case of extramedullary plasmacytoma with difficulties in making preoperative diagnosis.