CASE OF THE MONTH
Sinonasal Extramedullary (Extraosseous) PlasmacytomaThis 36-year-old male presented to his ENT physician with a history of right nasal mass and bilateral maxillary sinus disease. At surgery a maxillary sinus mucosal retention cyst was identified along with a right posterior nasal mass.
Microscopically the right posterior nasal mass was a very cellular hyperchromatic neoplasm with scattered numerous blood vessels. The tumor did not involve underlying bone. The overlying nasal mucosa was within normal limits. Immunohistochemical stains were performed showing positive CD 138 and kappa restricted by ISH. The diagnosis therefore was made of extramedullary plasmacytoma.
Extramedullary plasmacytoma comprises approximately 3-5% of all plasma cell neoplasm. 80% are primary (solitary) without evidence of tumor elsewhere. 20% are part of the generalized picture associated with multiple myeloma. Up to 25% of patients have a monoclonal gammopathy
(M component). This was not present within the patient however.
The diagnosis of extramedullary plasmacytoma warrants complete skeletal examination and clinical staging to determine the extent of disease and thus predict the outcome.
70% of patients with extramedullary plasmacytoma are alive at 10 years with a median survival of 79 years.
