Rhabdomyoma of the tonsillar fossa.

Extracardiac rhabdomyomas are very uncommon tumors comprising approximately 2% of the neoplasms of striated muscle origin. The adult extracardiac rhabdomyoma is generally characterized as a slowly growing, usually solitary lesion, which is nearly always found in the head and neck area of elderly persons. The most common reported head and neck subsites are the floor of the mouth, tongue, palate, lips, and cheeks. We report an unusual presentation of rhabdomyoma that should be included in the differential diagnosis of tumors presenting as a large tonsillar fossa mass. In our review of the almost 160 clinical notes reported in the literature, only 2 instances of tonsillar rhabdomyomas were found. The cytologic and immunohistochemical differential diagnoses of this tumor are also discussed.