A case of gastric plasmacytoma associated with Helicobacter pylori infection: improvement of abnormal endoscopic and EUS findings after H. pylori eradication

Double Extramedullary Plasmacytoma of the Stomach with a Long-term Endoscopic Follow-up

A 56-year-old woman was referred to our hospital with a growing gastric submucosal tumor. An upper endoscopic examination revealed two gastric tumors, an original polypoid tumor and a newly diagnosed superficial tumor. Boring biopsied specimens of the submucosal tumor showed gastric plasmacytoma; however, the other specimens showed no malignancy. Blood diseases were ruled out using various examinations; therefore, we diagnosed the tumor as extramedullary gastric plasmacytoma. The patient underwent laparoscopic distal gastrectomy, and both tumors were thus revealed to be plasmacytomas. We experienced a rare case with two differently shaped extramedullary gastric plasmacytomas without significant morphologic change during the follow-up.

Complete remission of gastric plasmacytoma following eradication of "Candidatus Helicobacter heilmannii"

This is the first case report of gastric plasmacytoma associated with "Candidatus Helicobacter heilmannii" ('H. heilmannii') infection. The patient was a 40-year-old woman with epigastric discomfort. Upper gastrointestinal endoscopy demonstrated a white granular lesion on the wall of the gastric body. Histological studies showed numerous eosinophilic globules expanding the lamina propria mucosae. Immunohistochemically, the cells with these globules stained positive for CD138, CD79a, immunoglobulin (Ig) M, and kappa light chain, but negative for CD20, IgG, IgA, and lambda light chain. A diagnosis of plasmacytoma was made. Although a Helicobacter pylori infection was not detected, the patient received H. pylori eradication treatment. Two months after H. pylori eradication treatment, an upper gastrointestinal endoscopy showed a reduction of the white granular lesion. Eighteen months after eradication treatment, endoscopy, endoscopic ultrasonography and histological studies revealed complete remission of the lesion. No relapse has been documented 30 months after the initial diagnosis of plasmacytoma. Retrospectively, analysis of biopsy specimens removed before eradication treatment demonstrated that this patient had 'H. heilmannii' infection. Therefore, H. pylori eradication therapy should be considered as a potential first-line therapy for early-stage gastric plasmacytoma with or without H. pylori infection.

Complete endoscopic resection of very early stage gastric plasmacytoma

Gastric plasmacytomas are very rare, and most are not detected until the disease has progressed to an advanced stage. However, there have been recent reports of cases of early-stage gastric plasmacytoma, in which neoplastic cells are confined to the mucosa or submucosa. Here we report a case of a very early stage gastric plasmacytoma that was confined to the lamina propria of the gastric mucosa. The lesion was successfully and completely removed by endoscopic submucosal dissection, and the surveillance endoscopy showed no recurrence during the follow-up of 40 months. This report appears to be the first documented case of complete endoscopic removal of a primary gastric plasmacytoma.