[Multiple myeloma of the sphenoid sinus: a case report].

Plasma cell neoplasms of the head and neck region can be extramedullary plasmacytoma of the bone, solitary plasmacytoma of the bone, and local manifestations of multiple myeloma. A 70-year-old male patient was admitted to our hospital with diplopia of four-day history. Magnetic resonance imaging showed soft tissue in the sphenoid sinus. Endoscopic biopsy was taken from the sphenoid sinus, which revealed multiple myeloma. Despite medical therapy for multiple myeloma, the patient died after a year.