RESUMEN
Rhabdomyomatous mesenchymal hamartoma is a rare skin lesion composed of a haphazard arrangement of skeletal muscle, adipocytes, and collagen. Lesions usually present as a solitary sessile papule or nodule on the head and neck in childhood. The etiology of this skin lesion is not clear, but it is thought to be caused by a migration error of the embryonic mesodermal tissues or a genetic defect predisposing to the formation of hamartoma. It may occur as part of Delleman syndrome or congenital malformations like thyroglossal duct cysts, low set ears, and sclerocornea. Herein, we present two cases of rhabdomyomatous mesenchymal hamartoma, including a 20-year-old man who had two asymptomatic erythematous papules on the chin since childhood and a 58-year-old woman with an asymptomatic solitary erythematous sclerotic plaque on the chin for 2 years. Histopathologically, the lesions exhibited normal epidermis, and mature striated muscle fibers arranged randomly within the dermis. Physical examination revealed no congenital abnormalities.