A Case of Concurrent Gastric and Pancreatic Plasmacytomas in a Patient With Multiple Myeloma: An Extremely Rare Entity

Abstract

Multiple myeloma (MM), a plasma cell tumor, is primarily a disease of the bone marrow. Extramedullary plasmacytoma, also a plasma cell tumor, is very rare in the gastrointestinal tract and the pancreas, and only a handful cases have been documented till now. Gastric and pancreatic plasmacytomas are usually seen in elderly patients; however, cases in patients as young as 32 years of age have been reported. Commonly, patients with gastric plasmacytoma present with nonspecific symptoms like epigastric pain, abdominal fullness, anorexia, and weight loss, or serious conditions like massive upper gastrointestinal bleeding and gastric outlet obstruction. Patients with pancreatic plasmacytoma commonly present with obstructive jaundice. In this article, we present the case of a 79-year-old man with a history of MM for 3 years, diagnosed with gastric and pancreatic masses, which turned out to be plasmacytomas. To our knowledge, simultaneous occurrence of gastric and pancreatic plasmacytomas is extremely uncommon with less than 5 cases reported in the literature. We also compiled all the individual cases of gastric and pancreatic MM that have been reported in literature till now.

Keywords: extramedullary multiple myeloma; gastric plasmacytoma; multiple myeloma; pancreatic plasmacytoma.

Figure 1.

Esophagogastroduodenoscopy revealed a large polypoid mass with central ulceration in the gastric cardia.

Figure 2.

(A) Endoscopic ultrasound (EUS) showing the gastric mass arising from the submucosal gastric layer, measured 29.9 × 19.7 mm in diameter. (B) EUS showing an irregular, well-defined, and heterogeneous solid mass with cystic components in the body of the pancreas measured 33.2 × 39.8 mm in diameter.

Figure 3.

Hematoxylin and eosin staining. (A and B) Histology of the gastric biopsy showing the presence of abundant atypical cells, which had eccentrically placed large nuclei with occasional multinucleation and with few mitotic figures (magnification, ×40 and ×100, respectively).

Figure 4.

(A) On immunohistochemistry (IHC), the cells showing clusters of monoclonal plasma cells, stain positive for CD138 (magnification, ×100). (B) On IHC, the cells showing clusters of monoclonal plasma cells, stain positive for Kappa, which was consistent with plasma cell neoplasm (magnification, ×100).