Primary plasmablastic plasmacytoma in the stomach of an immunocompetent adult: A case report.

Rationale: Extramedullary plasmacytomas (EMP) are tumors composed by a monoclonal population of plasma cells that arise in extraosseus tissues, occupying <5% of all plasma cell neoplasms. Gastrointestinal solitary extramedullary plasmacytoma is rare, just comprises about 5% of all EMPs. The most common site is small intestine. The gastric incidence is much rare and especially the plasmablastic plasmacytoma in the stomach.

Patient Concerns: A 65-year-old man had an epigastric discomfort and mass for about 2 months. Gastroscopy revealed a malignant tumor in the gastric body. Abdomen computed tomography (CT) showed that the gastric cavity was filled, and the irregular soft tissue shadow was seen in the greater curvature, and the enhancement was obvious. To get more tissue, we conducted stomach puncture biopsy. Pathology showed small-round cell malignant tumors. And immunohistochemical examinations revealed that the tumor tend to be a plasma cell tumor.

Diagnosis: Gastric plasma cell tumor.

Interventions: Distal gastrectomy was performed to treat the tumor.

Outcomes: In addition to ascites caused by hypoproteinemia, there were no postoperative complications. Postoperative pathologic report showed plasmablastic plasmacytoma. Histopathologic examination of the specimen revealed plasmablastic plasmacytoma originating in the stomach with transmural extension, but without lymph node metastasis. The patient is regularly followed up at a postoperative clinic and is doing well, and at present there is no plan for adjuvant treatment.

Lessons: Surgical resection is good option for gastrointestinal EMP.