Alveolar rhabdomyosarcoma of the paranasal sinuses in a 57-year-old woman with 1:16 translocation

Alveolar rhabdomyosarcoma is an uncommon tumor. It is a rare malignancy in adults and rarely occurs in paranasal sinuses in those aged older than 50 years. This report describes a locally invasive and destructive alveolar rhabdomyosarcoma arising in the ethmoid sinus of a 57-year-old woman. The small round blue cell tumors are positive for myogenin by immunohistochemistry and have a karyotype of 45, XX, -5, -13, der(16)t(1;1) (q21;q13) by cytogenetic analysis. Fluorescence in situ hybridization demonstrated a complex translocation with break apart of the FKHR region, which supports a diagnosis of alveolar rhabdomyosarcoma. This report characterizes this tumor through microscopic and cytogenetic analysis and emphasizes the importance of considering rhabdomyosarcoma in the differential diagnosis of small round cell tumors of the head and neck region in the middle-aged adults.