Vascular dysplasia of arteries in neurocristopathies: a lesson for neurofibromatosis.

In a 15-year-old girl suffering from congenital constipation, megacolon combined with a 'Ranken neuroma' of the rectum and a short aganglionic segment of distal colon was observed. The specific vascular alterations in the region of the Ranken neuroma (which has previously been described in cases of von Recklinghausen neurofibromatosis) were studied, with an emphasis on immunohistochemical methods. The results suggest that the pericytes are the cells primarily involved in the distinctive alterations of the blood vessels. Respecting the similarities of the location and vascular alterations in the neurocristopathies, von Recklinghausen neurofibromatosis and Hirschsprung's disease, to those seen in vascular fibromuscular hyperplasia, the possible pathogenetic relationships of these kinds of vascular malformations are considered.