Extramedullary plasmacytoma with colonic involvement: experience in a tertiary hospital.

A 71-year-old woman diagnosed with type II diabetes mellitus with severe iron deficiency anemia and positive fecal occult blood. Colonoscopy was performed, showing a soft mass in the ascending colon, with biopsies compatible with plasmacytoma and restriction for Kappa light chains. After bone marrow aspiration, associated IgG multiple myeloma was detected, so chemotherapy with VMP (bortezomib, melphalan and prednisone) was started. Colonoscopy six months later showed that the ulcerated lesion had a reduction in tumor size of up to 80%. A 27-year-old male with a history of kidney transplantation and symptoms of chronic diarrhea, colonoscopy was indicated with the finding of a large exophytic and ulcerated lesion in the cecum. Pathology revealed plasmacytoma with restriction of lambda light chains. After ruling out lesions in other locations, the patient was treated with immunochemotherapy according to the Bortezomib-Rituximab-Dexamethasone scheme, with subsequent complete clinical and endoscopic remission. Plasmacytoma accounts for < 4 % of plasma cell tumours. It may appear isolated or associated with another plasma cell neoplasm, mainly multiple myeloma. Its presence in the gastrointestinal tract is rare, being infrequent in the stomach or small intestine, and even rarer in the colonic tract (incidence 1/10,000,000). The clinical manifestations are similar to those of other colon neoplasms, while the treatment or prognosis may differ from those of other neoplasms. In patients with clinical suspicion, it is important to perform an early endoscopic study, especially in patients diagnosed with multiple myeloma.