Biopsy-proven spontaneous regression of a rhabdomyomatous mesenchymal hamartoma.

Rhabdomyomatous mesenchymal hamartoma (RMH) is a rare, benign, congenital tumor of the dermis and subcutaneous tissue comprised of skeletal muscle and adipose and adnexal elements. Although the majority of cases are an incidental finding in otherwise healthy patients, some have been reported in association with other anomalies. We present a full-term boy evaluated on day 2 of life for two lesions located on the midline of the lower back and right buttock that each appeared clinically as an atrophic, pink plaque.