S2214 A Rare Case of Secondary Extramedullary Plasmacytoma With Ileocecal Involvement

Abstract

Introduction: Extramedullary plasmacytomas (EMPs) are a rare type of plasma cell dyscrasia characterized by the neoplastic proliferation of plasma cells in soft tissue.EMPs share characteristics with multiple myeloma (MM) and can present as primary tumors or secondary to other plasma cell neoplasms.Herein we present an extremely rare case of a patient with established MM who was found to have an asymptomatic ileocecal mass with biopsy findings consistent with secondary EMP. Case Description/Methods: A 62-year-old female with a past medical history of MM and Ulcerative Colitis (UC) presented to the gastroenterology clinic for evaluation of her UC before consideration of an experimental therapy trial for her refractory MM.On presentation, she denied changes in her bowel habits or blood in her stool. Lab results 2 weeks prior to presentation were significant for leukopenia at 2.9k/uL, normocytic anemia with hemoglobin at 8.5gm/dL, Calcium 8.2 mg/dl, and total protein of 5.7g/dl. Colonoscopy showed nodular, ulcerated mucosa at the hepatic flexure as well as a large polypoid non-bleeding, non-obstructing, non-circumferential mass at the ileocecal valve. Histopathology of the mass returned positive for CD138 Kappa and negative for lambda AE1/AE3, CAM 5.2, GATA3, ER, consistent with a diagnosis of plasma cell myeloma. The patient continued on salvage chemotherapy but passed shortly thereafter (Figure). Discussion: Plasma cell neoplasms (PCNs) involving extra-osseous tissues are known as extramedullary plasmacytomas (EMPs).EMPs are further classified into primary EMPs, which are localized proliferation of clonal plasma cells in the absence of a systemic plasma cell dyscrasia, and secondary EMPs, where there is already a known primary PCN present. To the best of our knowledge, secondary EMP involving the small intestine and cecum is rare and only reported in a handful of case reports.Due to the indolent course of EMPs, nonspecific gastrointestinal manifestations may go undiagnosed in a subset of patients with MM. The prognosis of secondary EMP involving the gastrointestinal tract remains unclear, however, the limited data we have indicates a poor prognosis.On the other hand, novel treatments of MM continue to improve survival rates in patients with MM. As mortality in these patients decreases, the incidence of secondary EMPs is expected to proportionately rise as well. As such, more data is needed to understand how to monitor and treat this patient population for extramedullary involvement in order to generate good outcomes.Figure 1.: Large polypoid non-bleeding, non-obstructing, non-circumferential mass at the ileocecal valve before and after biopsy.