A case of infant congenital smooth muscle hamartoma

A case of infant congenital smooth muscle hamartoma(CSMH) is reported. A 4-month-old boy presented with light brown hyperpigmented plaque sized about 4 cm × 8 cm on the left back at birth. Prominent vellus hairs were observed on the lesion and the border was not clear. Histopathological examination showed increased smooth muscle bundles interlacing between collagen fibers in the dermis. The diagnosis of CSMH was made. No treatment was given due to the benign behavior of CSMH.