Molecular Basis of Synovial Sarcoma and the Rare Case of its Localization in Palatine Tonsil: A Review of the Literature

Synovial sarcomas (SS) are rare soft tissue malignant tumors that mainly arise from the lower extremities, especially the lower thigh-knee region. The literature has shown that this tumor may be observed in uncommon regions such as the abdominal wall and the head and neck region which are non-synovium-lined spaces. SS rarely occurs in the head and neck region, as only 3-10% of these neoplasms appear in this region. The parapharyngeal space is the most common location, whereas primary SS of the palatine tonsil is extremely rare as only a few cases of primary tonsillar SS have been described. It is considered as a high grade malignant tumor, however current investigation regarding its clinical and histopathological features revealed in all these cases a biphasic morphology. Molecular analyses detected a typical SYT gene t(X;18) (p11; q11) translocation and a representative SYT/SSX1fusion type. Immunohistochemical analysis recorded cytokeratin OSCAR, Bcl-2, EMA, vimentin, TLE1 and PGP 9.5, were diffusely positive. The aim of the current review was to present the molecular basis of SS and SS rare location in palatine tonsil.