Nasopharyngeal rhabdomyoma. Report of case (light and electron microscopic studies) and review of the literature.

Rhabdomyoma is an extremely rare benign tumor originating from the skeletal or cardiac muscle cells. Only 87 cases of rhabdomyoma have been reported to date, 70% occurring in the head and neck areas. The authors present the fourth case of rhabdomyoma of the nasopharynx. The tumor appeared in an 18 year old woman with hypacusis. Examination of the epipharynx showed a 2 x 1,5 cm tumor, extending from torus tubarius down to the soft palate. Light microscopy disclosed areas and islands of polymorphous large cells with abundant eosinophilic cytoplasm. Cross striations were focally visible with special PTAH staining. Electron microscopy revealed parallel and haphazardly arranged fibrillar bands (myofibrils) with irregularly and periodically arranged densities corresponding to Z lines. The pecularities of our case were abundant cystically dilated rough endoplasmatic reticulum and the absence of cytoplasmatic glycogen.