Sarcoma sinovial intramandibular. A propósito de un caso Synovial sarcoma of the mandible. A case report

SUMMARY Introduction: Synovial sarcoma is an unusual soft tissue tumour of the head and neck. It is extremely rare on the man- dible. Case presentation: We present here a case of a 74 year-old man previously diagnosed and treated of jaw osteo- sarcoma. Five years later the patient showed a neoplasm recurrence on the remaining mandibular condyloid, exten- ding to the temporal bone. The diagnosis with light micros- copy, immunohistochemical staining, and ultrastructure was monophasic synovial sarcoma. The characteristic chromoso- mal translocation t(x;18) was founded on the cytogenetic study, confirming the diagnosis of local recurrence of syno- vial sarcoma. The previous biopsy was misdiagnosed. Con- clusions: The monophasic synovial sarcoma needs a diffe- rential diagnosis with other neoplasms. More than 50% of the cases shows recurrence and have a high rate of distant metastases. Adequate tissue sampling, immunohistochemi- cal, ultraestructural and characteristic chromosomal translo- cation findings are necessary for diagnosis.