Primary Gastric Plasmacytoma: A Rare Cause of Melena

Abstract

Purpose: Extramedullary plasmacytomas (EMP) are particularly rare, accounting for less than 3-4% of all plasma cell tumors. Almost 90% of cases with EMP develop in the head and neck area including the sinuses, nasopharynx, and tonsils. We report a case of primary gastric plasmacytoma and its clinical, endoscopic, and histological manifestations. Results: A 52-year-old man with hypertension and dyslipidemia presented with a one week history of melena, fatigue, early satiety, and epigastric discomfort. On upper endoscopy, a 3 cm mass was identified opposite the cardia along the posterior wall of the stomach at the body/fundus junction [Image 1]. On endoscopic ultrasound, a 3.3 cm mass was found in the submucosa of the stomach, with involvement of the muscularis propria [Image 2]. Biopsy specimens of the mass revealed gastric mucosa with a mild to moderate inflammatory infiltrate composed of small lymphocytes with plasma cells. Immunohistochemical stains performed on the neoplastic cells demonstrated the presence of plasma cell marker CD138, monotypic for immunoglobulin kappa light chains. CD20, a B-cell marker, was not expressed by the malignant cells. The morphology of the plasma cells in conjunction with immunohisto-chemistry was consistent with primary gastric plasmacytoma. Marginal zone B-cell lymphoma (MALT) was considered unlikely because of the absence of monocytoid B-cells, CD20 B-cell marker, centrocytes and small lymphoid cells. A bone marrow biopsy showed no evidence of lymphoma or plasma cell neoplasm. Conclusion: Primary gastric plasmacytoma is an extremely rare diagnosis with scattered case reports in the literature. Though no general consensus exists on treatment, radiation therapy and surgical resection are two modalities that have been used.Figure: Mass.Figure: EUS.