Cutis marmorata telangiectatica congenita (CMTC) is a birth defect involving the skin and blood vessels. It is characterized by patches of marbled-looking skin (cutis marmarota), small widened blood vessels under the skin (telangiectasia) and varicose veins (phlebectasia). The skin findings most often occur on the legs, but may also occur on the arms and trunk. The face is only rarely involved. CMTC usually only affects a specific area of the skin, although there have been a few cases of CMTC over the whole body. It may occasionally occur along with open sores (skin ulceration) or skin atrophy. The skin symptoms associated with CMTC generally improve with age. CMTC can occur alone or along with a variety of other birth defects, particularly those involving undergrowth or overgrowth of the same arm or leg. Most cases are thought to be sporadic (non-inherited), although rare cases have been observed in families.