Rhabdomyoma of the larynx recurring after 12 years: immunocytochemistry and differential diagnosis.

Rhabdomyoma is a rare tumor of skeletal muscle origin which can occur in different localizations. The head and neck region is a site of predilection for the adult type. Its absolutely benign behavior makes correct diagnosis crucial. In this study, a case of an extracardiac rhabdomyoma of the larynx was found to recur 12 years after initial treatment. Following its surgical removal, histology showed typical patterns of an adult type of rhabdomyoma with focal cross-striations. Immunocytochemically, all applied muscular markers were positive. Electron microscopy revealed muscular filaments with cross-striations and glycogen granules. These findings showed that immunocytochemistry plays an important role in differential diagnosis and the need for possible further treatment.