Rhabdomyomatous Mesenchymal Hamartoma: An Acquired Plaque-Type Variant Case Report.

Rhabdomyomatous Mesenchymal Hamartoma (RMH) is a rare, typically congenital, benign hamartomatous tumor of the dermis and subcutaneous tissue. The lesions consist of disordered collections of mature skeletal muscle and varying amounts of additional mesenchymal-derived tissue. RMH is usually a solitary, polypoid, midline lesion of the head or neck in an infant or child, which may occur in conjunction with multiple ectodermal/mesodermal abnormalities. More recently, patterns of RMH occurring in adults have been described. Herein, we present an adult patient who presented with an RMH on the chin, followed by a clinical course and histologic evaluation. This case demonstrates an uncommon variant of an acquired, plaque-type RMH with unique histologic properties.