Rhabdomyomatous mesenchymal hamartoma presenting as a skin tag in a newborn

Abstract

Rhabdomyomatous mesenchymal hamartoma (RMH) is a rare congenital lesion in the dermal and subcutaneous tissues of newborns that was first described as a striated muscle hamartoma in 1986 and named in 1989.1 Since then, 65 cases have been reported in the literature, some in association with other congenital abnormalities.2, 3 Most cases have been described in young patients on the head and neck, but cases have also been reported on the tongue, perianal region, vagina, and great toe.4 On histologic examination, RMH consists of striated muscle bundles, adipose tissue, blood vessels, collagen, and nerves.5 We report a case of a solitary RMH presenting as a skin tag on the midline chin of a newborn boy.