Multiple Myeloma Associated GI Polyposis

Abstract 5009

Multiple myeloma is a neoplastic proliferation of monoclonal plasma cells that can result in osteolytic bone lesions, hypercalcemia, renal impairment, bone marrow failure, and the production of monoclonal gammopathy. The gastrointestinal tract is rarely involved in myeloma. GI polyposis is a rare manifestation of extra-medullary disease in multiple myeloma. Such cases usually present as gastrointestinal hemorrhage or intestinal obstruction.

A 53-year-old African American male recently diagnosed with multiple myeloma presented with three-day history of rectal bleed and fatigue. EGD showed multiple raised, polypoid, rounded lesions with a superficial central ulceration in the stomach. Colonoscopy showed similar lesions in the ascending and transverse areas of the colon that ranged in size from 5 to 16 mm in diameter. Biopsies showed that these polyps were made of plasma cells. A bone marrow biopsy showed diffuse involvement (greater than 90%) of bone marrow with multiple myeloma with anaplastic features. The patient was started on bortezomib at diagnosis, however, he passed away a few weeks later.

This type of metastatic disease has been described in isolated case reports in the literature, while solitary GI plasmacytoma has been reported more frequently. In rare cases, multiple myeloma can involve the GI tract which may lead to bleed or obstruction. This involvement is likely a marker of aggressivity. This example of extra-medullary disease in myeloma is an uncommon variant with features of poor prognosis and dedifferentiation.