We report on two patients with clinical manifestations consistent with a diagnosis of macrocephaly-cutis marmorata telangiectatica congenita (M-CMTC). Both showed macrocephaly with high forehead, overgrowth, capillary hemangiomata involving philtrum, nose, and lips, and redundant skin. In addition, the first had cutis marmorata and joint laxity. The second had postaxial polydactyly of hands and feet, cutaneous syndactyly of third and fourth right fingers and of second and third right toes without evident cutis marmorata. A magnetic resonance imaging scan showed cerebral alterations in both patients. The first had bilateral cortical dysplasia with frontal bilateral myelinization defect of corona radiata. The second had mild intertonsillar widening, cavum septi pellucidi, small porencephalic areas in the anterolateral region of cellae, and subsequently developed a nonobstructive hydrocephalus. Reviewing all reported cases we propose a new criterion for M-CMTC diagnosis.