Multiple myeloma
An abdominal CT scan (Figure D) showed gastric and whole intestinal wall thickening of up to 2 cm. Pathology (Figure E) demonstrated that diffuse plasmacytoid cells, eosinophilic granulocytes, and lymphocytes infiltrated into the lamina propria. Immunohistochemically, the plasmacytoid cells were positive for the common plasma cell marker CD38, and in situ hybridization indicated that they were kappa-Ig light-chain restricted (Figure F).
Figure D
Results of the subsequent bone marrow aspirate revealed 27.5% atypical plasma cells. Serum electrophoresis and immunofixation showed an M spike of IgA-kappa. Together, these findings confirmed a final diagnosis of a multiple myeloma (MM) involving the whole gastrointestinal (GI) duct, which was the cause of his melena.
Figure E
MM is a malignant hematologic neoplasm, primarily involving the bone marrow, and has a potent tendency to involve other organs and to present with various clinical manifestations.1
The clinical features of MM with GI involvement are uncommon. Patients may present with nausea, vomiting, diarrhea, protein loss, malabsorption, intestinal obstruction, and hemorrhage. Endoscopic findings can manifest as four types: a discrete ulcer, ulcerating mass, thickening of the mucosal fold, and mucosal polyp.2
Figure F
However, GI bleeding in MM has only been reported in a few patients. A biopsy reaching the submucosal layer and bone marrow biopsy is essential. Diagnosis of MM as a cause of the GI duct wall edema and multiple small intestinal polypoid ulcers is challenging. An interdisciplinary approach is mandatory to establish such a diagnosis.
References
1. Kyle RA, Rajkumar SV. Multiple myeloma. N Engl J Med. 2004;3518:1860-73.
2. Karam AR, Semaan RJ, Buch K, et al. Extramedullary duodenal plasmacytoma presenting with gastric outlet obstruction and painless jaundice. Radiol Cases. 2010;4:22-8.
