Cutis marmorata telangiectatica congenita (CMTC) is a congenital cutaneous vascular malformation that is diagnosed on the typical clinical findings of persistent cutis marmorata, telangiectasia, phlebectasia, occasional ulceration and atrophy, and tendency for clinical improvement. Histopathologic findings seldom have been reported. We report a case of CMTC with atypical histopathologic findings of proliferation of vasculature in addition to dilated capillaries in the dermis. We have reviewed all cases of CMTC with histopathologic findings published in the English-language literature. The most common and prominent finding was dilation of capillaries and veins in the dermis (13/15 cases). Two cases, including our own, demonstrated proliferation of vascular channels. The implications of vascular proliferation on the clinical course of CMTC are unclear. (J Am Acad Dermatol 2003;48:950-4.)