Perianal Rhabdomyosarcoma

Abstract
Rhabdomyosarcoma is a well-recognized malignant mesenchymal neoplasm most frequently arising in the skeletal muscles of the extremities.1-9 In addition, it may represent a component of a neoplasm in which other mesenchymal or mesodermal elements may be identified: the so-called malignant mesenchymoma, or mixed mesodermal tumor, which is most frequently observed in the genitourinary tract.10 Documented examples of rhabdomyosarcoma have also been noted in such unusual sites as the parotid gland, thyroid, adrenal, bronchus, lung, ovary, and cerebellum.10-12 In some of the neoplasms in these latter structures other tissues have not been identified, and it has been suggested that they are derived from undifferentiated mesenchyme in such structures.10 Only a few examples of rhabdomyosarcoma arising in the gastrointestinal tract have been recorded. These have occurred in the tongue, oropharynx, esophagus, sites which normally possess skeletal muscle,10 and in bile ducts.3 Benenati13 referred to a