Plasmacytoma as a Mimicker of Colonic Carcinoma in an Elderly Man

Abstract

Multiple myeloma is a neoplastic proliferation of monoclonal plasma cells. Although it is usually restricted to the bone marrow, extraskeletal spread in the form of localised extramedullary collections of malignant plasma cells (plasmacytomas) can occur. However, gastrointestinal tract involvement in multiple myeloma is rare and overt gastrointestinal bleeding from plasmacytoma is uncommon. We report a case of colonic plasmacytoma which presented with bleeding per rectum and was initially misdiagnosed as colonic neuroendocrine carcinoma. Later the patient presented with recurrence of the colonic mass along with multiple lytic bone lesions. The diagnosis of colonic plasmacytoma with progression into multiple myeloma was given. We also discuss here the diagnostic difficulty of plasma cell neoplasms in small biopsies of the colon.

<p>Lower Gastrointestinal Involvement in Multiple Myeloma: A Case Report</p>

“…Extramedullary plasmacytoma occurs in around 3-20% of plasmacytomas in various studies, and involvement of the colon is rare. 1,8 It is commonly seen in upper respiratory tract (82%) with the rest in the urinary bladder, brain, thyroid, skin, etc. Involvement of GI tract is seen in less than 10% of cases, frequent in the small intestinal tract, followed by the stomach colon and esophagus.…”

“…Involvement of GI tract is seen in less than 10% of cases, frequent in the small intestinal tract, followed by the stomach colon and esophagus. 8 Involvement of the GI tract in MM occurs later in disease progression or relapsing disease. 9,10 Bleeding is more common in advanced stages of MM and likely an end-stage event.…”

“…The prognosis of GI involvement is unknown; however, studies have indicated a poor prognosis. 1,8,9 Multiple myeloma is a systemic disease affecting multiple organ systems with varying atypical presentations. Presence of GI bleeding with inconclusive endoscopic and imaging studies may be related to hematopoietic malignancies which should be addressed further.…”