RESUMO
Objective:To describe an intranasal mass initially diagnosed and treated as benign that eventually turned out to be a malignant extramedullary plasmacytoma of the maxillary sinus and to review the literature on its presenting signs and symptoms, diagnosis, management and pathophysiology. Methods: Design: Case Report Setting: Tertiary Public Hospital Patient: One Results: A 45-year-old male with persistent nasal obstruction and intermittent epistaxis underwent several biopsies of a mass shown on computed tomography scans as heterogeneously enhancing, expansile, occupying the left maxillary sinus with extension into the left nasal cavity with areas of erosion. Immunohistochemical staining was negative for cytokeratin (CK) and leukocyte common antigen (LCA). Complete excision yielded a final histopathologic interpretation of plasmacytoma. Laboratory examinations excluded multiple myeloma. The final diagnosis was extramedullary plasmacytoma and he was treated with post-operative adjuvant radiotherapy. Conclusion: Plasmacytoma may present in the sinu-nasal region and be part of a systemic disease like multiple myeloma. A high index of suspicion and thorough initial histopathological work-up may help in establishing a definitive diagnosis and providing optimum treatment.