[A case of extramedullary plasmacytoma of the stomach].

A 51-year-old man with extramedullary plasmacytoma of the stomach is presented. He complained of epigastralgia. Barium meal revealed 2 submucosal tumors in the gastric body. Laboratory investigations showed neither hypergammaglobulinemia nor proteinuria. Bone X-ray examinations were not remarkable. There was tumor invasion to the pancreas and metastasis to the perigastric lymph nodes. Proximal gastrectomy was performed, and the patient died 5.5 years after the operation. Histologically, the proliferation of atypical plasma cells with eccentric nuclei was seen. Those cells invaded all layers of the stomach. The tumor cells were pyroninophilic and contained Russel bodies. Immunohistochemical study using the immunoperoxidase technique demonstrated IgG and lambda-light chains in the tumor cells.