Plasmacytoma of the Head and Neck: Case Series and Review of the Literature.

Solitary plasmacytoma is a rare neoplasm characterized by localized proliferation of monoclonal plasma cells and is classified as solitary bone or solitary extramedullary plasmacytoma. Here, we present two rare cases of plasmacytoma of the head and neck. The first is a 78-year-old male who presented with a 3-month history of epistaxis and progressive obstruction of the right nasal passage. Computerized tomography (CT) imaging revealed a mass in the right nasal cavity with destruction to the maxillary sinus. An excisional biopsy was performed revealing anaplastic plasmacytoma. The second is a 64-year-old male with a past medical history significant for prostate cancer who presented with a 2-month history of left ear pain and progressive non-tender temporal swelling. A PET/CT revealed a highly avid, destructive, and lytic left temporal mass with no other evidence of distant disease. A left temporal craniectomy and infratemporal fossa dissection revealed plasma cell dyscrasia with monoclonal lambda in situ hybridization. Although plasmacytomas are uncommon tumors of the head and neck, they may mimic other entities that require different treatment. Prompt and accurate diagnosis is critical for appropriate therapeutic decisions and prognosis.