Synovial sarcoma of the larynx and hypopharynx

Synovial sarcoma represents a mesenchymal malignancy of unknown histogenesi s that most often occurs in the lower limbs of young adults. The head and n eck region is a relatively rare location, in which the hypopharynx and lary nx are, respectively, the most and least often affected anatomic sites. His tologically, synovial sarcomas are classified into monophasic and biphasic variants. Immunohistochemistry plays a major part in the differential diagn osis, enabling the demonstration of epithelial differentiation. Both monoph asic and biphasic synovial sarcomas are characterized cytogenetically by th e reciprocal translocation t(X;18)(p11.2;q11.2) between chromosomes X and 1 8. Two cases of synovial sarcoma arising in the larynx and in the hypophary nx and in which cytogenetic analysis detected a diagnostic t(X;18) chromoso me aberration are reported here.