[Synovial sarcoma of the head and neck: a case report of parapharyngeal region and review of the literature].

Synovial sarcoma is a clinically and morphologically well defined entity that has been described extensively in Literature. It occurs primarily in the para-articular regions, usually in close association with tendon sheaths, bursae and joint capsules. On rare occasions it is also encountered in areas without any apparent relationship to synovial structures, as in the parapharyngeal region or the abdominal wall. It is considered the fourth most common type of sarcoma (7-10%) after malignant fibrous histiocytoma, liposarcoma and rhabdomyosarcoma. There are three histological variants: the classical biphasic, the monophasic fibrous type and the monophasic epithelial type (the biphasic and monophasic fibrous type are equally common). Clinical sign complaints are subtle and at times noted 20 years before diagnosis. The course of the disease is slow and insidious. The most typical presentation is that of a palpable deep-seated swelling or mass associated with pain or tenderness. Patients with synovial sarcoma in the head and neck (10%) tend to have difficulties in swallowing and breathing and not infrequently have alteration or loss of voice. Head and neck synovial sarcoma seem to originate from the paravertebral connective tissue spaces and manifest themselves as solitary retropharyngeal or parapharyngeal masses near the forking of the carotid. Additional cases in this general area have been reported in the soft palate, tongue, maxillofacial region, mandible corner, sternoclavicular region, scapular region and the cervical oesophagus. As in other types of sarcoma, the principal sites of metastases are the lung, but many make their appearance many years after the initial diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)