CT and MRI findings of a solitary extramedullary plasmacytoma of the oropharynx: case report.

We report a case of solitary extramedullary plasmacytoma (SEP) of the oropharynx. A 53-year-old man presented who had had bloody phlegm and a sore throat for a few days. A mass was endoscopically detected in his right posterior oropharyngeal wall, and biopsy revealed a neoplasm consisting of a uniform population of plasma cells. Computed tomography (CT) showed a broad-based papillary soft tissue density mass projecting into the oropharynx from the right posterior wall of the pharynx, and post-contrast CT showed marked enhancement of the tumor. The tumor showed slightly higher signal intensity compared with surrounding muscle on MR Tl-weighted images (T1WI) and high signal intensity on MR T2-weighted images (T2WI). The mass showed homogeneous enhancement on post-contrast T1WI. Further clinical examination showed an absence of multiple myeloma (MM). The patient was diagnosed as having SEP. Following radiation therapy, a reduction in tumor size was observed. Although SEP is a rare tumor, it should be included in the differential diagnosis of tumors of the oropharynx because of its imaging similarities to other, more common malignant tumors, such as squamous cell carcinoma and lymphoma.