The agyria-pachygyria complex: a spectrum of cortical malformations.

Agyria-pachygyria is a relatively common brain malformation in humans as shown by the recent experience with CT scan and MR imaging. However, the specificity of imaging is not completely established and it is not known whether all cases with a thick cortical ribbon and a smooth surface correspond histologically to actual agyria-pachygyria or may belong to different pathological anomalies such as polymicrogyria. The extent, distribution and detailed structure of agyria-pachygyria vary widely and the clinical features are accordingly very diverse. Rather than one entity, pachygyric cortical abnormalities form a broad spectrum that raises different clinical, nosological and genetic problems. Therefore, a precise analysis of each case is necessary to establish the prognosis and risk of recurrence.