Answer:
Sturge-Weber syndrome falls in the category of low-flow capillary malformations. It was originally described in 1879 by Sturge for a 6 year-old girl with a capillary stain of her right face, buphthalmos (congenital glaucoma), and focal left-sided seizures. A strict definition of the Sturge-Weber syndrome includes vascular anomalies of the upper facial dermis, choroid plexus, and ipsilateral leptomeninges. It occurs with equal gender incidence, and occurs sporadically; it is thought to be due to an error in morphogenesis within a specific region of the cephalic neural crest, causing abnormal vasculature in the upper facial dermis, choroid, and pia-arachnoid. If the port-wine mark is located within the opthalmic areas alone (V1) or extends also into the V2 and V3 area, the risk of associated ocular and intracranial vascular anomalies is high. If, in contrast, the port wine stain is within the V2 and V3 areas only, the associated risk is not high. The area of dermal staining can involve the face, neck, trunk, and extremities. There can be associated overgrowth of cranial tissue and skeleton, producing macrocephaly and midfacial hypertophy in the area covered by the stain. These patients also have intracranial calcification, especially in the parieto-occipital area, reflecting mineral deposition in the cerebral cortex beneath the vascular anomaly in the leptomeninges.
Kasabach-Merritt syndrome: refers to a bleeding disorder that results from profound thrombocytopenia (2000-40000) that is associated with either a large hemangioma or extensive hemangiomatosis. In this condition, platelets have a shortened survival time, and platelet thrombi develop within the hemangioma. The K-M syndrome classically occurs during the early postnatal period of rapid hemangiomatous growth. The clinical presentation consists of acute hemorrhage (GI, pleural, peritoneal or CNS) or a rapid increase in the size of the hemangioma due to intralesional bleeding. Petechia and ecchymosis appear on and around the hemanigioma, which can appear cellulitic from thin, shiny overlying skin.