Perianal rhabdomyosarcoma presenting 21 months after hamartoma excision.

Perianal rhabdomyosarcoma is a rare type of tumor with a relatively poor prognosis. We present the case of a patient who presented with a cutaneous perianal hamartoma at the age of 6 weeks. 21 months latter a recurrent mass at the excision site proved to be an embryonal rhabdomyosarcoma involving the anal sphincter. A pathologic review of the two specimens confirmed their relatedness. This report highlights the need to maintain a high level of suspicion in cases of recurrence following excision of a benign lesion.