Solitary extramedullary plasmacytoma arising in the pterygoid fossa

A case of solitary extramedullary plasmacytoma of the left pterygoid fossa is presented, which is an unusual location for such tumors. A 54-year-old male patient was admitted for retro-orbital and left-sided facial pain which had persisted for several months. Physical, nasal endoscopic and optic examinations showed no abnormalities. No palpable cervical lymph nodes were found. MRI revealed a 2-cm mass in the left pterygoid fossa. A biopsy was carried out and the resulting histological evaluation of the mass confirmed a plasmacytoma. A comprehensive work-up, including bone marrow biopsy, total-body skeletal survey, technetium scintigrams, determination of urine Bence-Jones protein and serum myeloma protein, chest radiograph, total blood count and urinalysis, was carried out in order to rule out multiple myeloma. All of these studies were unremarkable in terms of a systemic disease and therefore the patient was diagnosed as having a solitary extramedullary plasmacytoma of the pterygoid fossa. He was referred for radiation therapy, receiving irradiation of 50 Gy for 6 weeks. The clinical manifestations, imaging findings, pathology and treatment procedures of extramedullary plasmacytoma are described, together with a review of the literature.