Stenogyria - Not only in Chiari II malformation

Stenogyria, meaning multiple small compacted gyri separated by shallow sulci, is reported in the literature in association with Chiari II malformation (CM II) which in turn is reported in association with myelomeningocele (MMC). The authors present five cases of stenogyria (and other abnormalities found in CM II, like callosal hypoplasia/dysplasia, agenesis of the anterior commissure, hypoplasia of the falx cerebri) in children without the history of MMC or any other form of open spinal dysraphism. In these cases stenogyria was associated with Chiari I malformation, rhombencephalosynapsis and spina bifida. Stenogyria, which is not a true neuronal migration disorder, should not be mistaken for polymicrogyria which is also present in CM II. It is histologically different from polymicrogyria because the cortex is normally organized. Also on MRI, the general sulcal pattern is preserved in stenogyria, while it is completely distorted in polymicrogyria. The authors conclude that features traditionally attributed to CM II, like stenogyria, occur not only in the population of patients with MMC as opposed to the widely accepted theory.