More Than Polyps: A Rare Case of Gastric Plasmacytoma

Abstract

INTRODUCTION. Plasma cell neoplasms can be divided into four pathology types: multiple myeloma, plasma cell leukemias, solitary plasmacytoma of the bone and extramedullary plasmacytoma. Extramedullary plasmacytoma (EMP) is very uncommon, approximately 2-5% of all plasma cell neoplasms. Gastrointestinal (GI) involvement occurs in only 5% of patients with EMP. Occurrence of different types of plasma cell neoplasms present at once has not been well described. We report the case of a middle aged Caucasian man with solitary sacral plasmacytoma, presenting with concomitant finding of polypoid gastric plasmacytoma. CASE PRESENTATION. A 56-year-old male, with history of peptic ulcer disease and solitary right sacral plasmacytoma, presented with generalized weakness and low Hb (5.4g/dL). Physical exam showed pallor and mild tachycardia. There were no signs of active GI bleed but stool guaiac was positive. Laboratory investigations showed elevated alkaline phosphatase (266 U/L) with normal liver and renal function. Esophagogastroduodenoscopy findings included multiple 1-1.5cm polypoid lesions in lesser curvature of stomach and hiatal hernia, without evidence of bleeding. Histological examination showed diffuse plasma cell infiltrate of lamina propria with large atypical giant cells and immature forms, suggestive of plasma cell neoplasm involving gastric mucosa. Recurrent drops in Hb were attributed to hemophagocytic syndrome. The patient was eventually stabilized and discharged with surveillance by Hematology and Gastroenterology practices. DISCUSSION. About 80% of EMP occurs in the upper respiratory tract, with only 5% of cases being of GI origin, most commonly affecting the small bowel, stomach, colon and esophagus respectively. EMP is predominantly described in Japanese females of 56 years median age. Although multiple site EMP has been sufficiently reported, the combination of different types of plasma cell neoplasms present at once has not been well described. In our case, diagnosis of two different types of plasma cell neoplasms was made on a middle aged Caucasian man, providing unique characteristics from diagnostic and epidemiologic standpoints when compared to the current available data. CONCLUSION. Further identification and reporting of cases of such unique nature are necessary to better understand the incidence of combined plasma cell neoplasms, particularly with GI involvement.2682_A Figure 1. EGD showing 1.5 cm and a 1cm polypoid lesions noted in the lesser curvature of the body suggestive of gastric polyps. A biopsy specimen was obtained from each polyp and sent to the histopathology lab for analysis.2682_B Figure 2. Up: Cytoplasm staining for CD 138/ CD 38 which is plasma cell lineage. Down: Clonal stain for lambda monoclonal positive. Suggestive of monoclonal plasma cell neoplasm Kappa is negative polyclonal2682_C Figure 3. Up: Gastric surface area- not normal crypts reactive. Lamina priopria expanded-small blue cells. Down: Crypts with plasma cells and nucleus pushed to the side and paranuclear halo- typical of plasma cell features