Biphasic parapharyngeal synovial sarcoma: a cytologic and immunocytologic report of a case

BACKGROUND: Synovial sarcoma is a rare soft tissue sarcoma in the head and neck region and parapharyngeal space. There is no previous cytologic report of synovial sarcoma of parapharynx. The cytologic and immunocytochemical findings of a parapharyngeal biphasic synovial sarcoma together with diagnostic pitfalls are described. CASE REPORT: A 21-year-old girl presented with a 6-month history of progressive right arm pain, neck mass and upper aerodigestive tract obstruction. On physical examination there was a large painless mass arising from the right-sided parapharyngeal space causing airway obstruction. Initial magnetic resonance imaging (MRI) revealed a large tumor in the right-sided parapharyngeal space. Fine needle aspiration through cervical region was performed and was reported as benign spindle cell tumor. Smears were cellular and composed mostly of tight and loose clusters of spindle cells. Epitheloid cells could also be identified intermingled with them. She underwent near total resection of the tumor. Pathologic report disclosed the diagnosis of synovial sarcoma. She then received postoperative adjuvant external radiotherapy. CONCLUSION: Due to rarity of this tumor in this region and nonspecific cytologic features, we could not differentiate this tumor from the other more common spindle cell neoplasms. Considering synovial sarcoma in this region and immunocytochemistry can be helpful in rendering a correct initial diagnosis of this tumor.