RESUMEN
Multiple myeloma is a malignant plasma cell proliferation located in the bone marrow and bones. It can secondarily manifest with extraosseous involvement, but the gastro-intestinal tract locations are rare. We report 3 cases of gastric and colonic localizations of myeloma in two males and one female, aged 66, 71 and 77years. Multiple myeloma had been diagnosed 1 to 7years before. Digestive symptoms were epigastric pain, rectal bleeding or an obstructive syndrome. Endoscopy revealed ulcerated and budding tumors in the stomach, and nodular pseudo-polypoid tumor formations or an ulcerated erythematous area in the colon. Histopathological examination of the biopsies showed a diffuse tumor cell proliferation in the lamina propria composed of cells with a plasmacytoid or plasmablastic appearance, expressing plasma cell markers such as CD138 on immunohistochemistry. The 3 patients died in the weeks following the diagnosis. The prognosis of digestive localizations of multiple myeloma remains very poor despite new therapies. In the presence of any digestive symptoms in these patients with multiple myeloma, more systematic endoscopy may allow an earlier diagnosis and the implementation of more effective therapies.