Linear congenital smooth muscle hamartoma with follicular spotted appearance

Congenital smooth muscle hamartoma (CSMH) with follicular spotted appearanc e is a rare clinical variant of CMSH in which patients have marked perifoll icular papules in the patches, A linear distribution of CSMH is also extrem ely rare. We report a 16-year-old Korean girl with this uncommon form of CS MH who had linearly arranged, hyperpigmented lesions with follicular papule s extending from the right flank to the right lower leg from birth. Patholo gical findings, including immunohistochemical stains, were consistent with smooth muscle hamartoma. To date, there are only four reports on this rare, follicular form and one report on the linear form of CSMH in the literatur e. This paper describes the first combined occurrence of follicular spotted lesions and linear arrangement in CSMH.