[Sylvian stenosis with networks of the Moya-Moya type. Anatomo-clinical observation].

The authors report an angiographic observation, where a stenosis of the left middle cerebral artery, with Moya-Moya networks, is described. The anatomical study has shown an atresy of the middle cerebral artery, and has confirmed the hypothesis of a supplying role played by the Moya networks. Most of their anatomical findings are in agreement with a malformative aspect, which is speculated by the authors to be related to the failure, at the embryon level, of a good development of the middle cerebral artery; in this way, Moya might represent the remaining features of primitive plexiform networks. From this particular anatomical observation, the authors discuss some nosological problems and propose the hypothesis of several groups, which may be related to the moment when the stenosis is suspected to occur.