[Smooth muscle hamartoma in volar skin].

We report the case of a 12-year-old girl with a smooth muscle hamartoma of the right index finger. Smooth muscle hamartoma (SMH) is a congenital, relatively common disorder typically with predominance of autochthonal arrector pili muscles. An SMH can also rarely originate from smooth muscles of vessels in palmoplantar skin with the absence of pilosebaceous units. Because of overlapping histological features, the possibility of Becker's nevus being identical or associated with SMH has often been suspected by some authors.