Generalized cortical dysplasia manifested by diffusely thick cerebral cortex
G. Marchal, F. Andermann, D. Tampieri, Y. Robitaille, D. Melanson, B. Sinclair, A. Olivier, K. Silver and P. Langevin
Department of Neurology, McGill University, Montreal Neurological Hospital, Quebec, Canada.
Unilateral or bilateral rolandic macrogyria has been described as a cause
of epilepsy and, in some cases, retardation. Tissue from the periphery of
these lesions shows the changes of focal cortical dysplasia. Evidence
reported herein suggests that cortical dysplasia may also be generalized.
Two patients with intractable epilepsy and mental retardation had diffusely
abnormal, thick cortex, shallow gyri, and poor demarcation of gray and
white matter. One patient had an anterior callosotomy that led to
considerable improvement of the epilepsy. Cortical layers 5 and 6 could not
be differentiated on biopsy material. The white matter was poorly
myelinated and contained clusters of heterotopic neurons. This syndrome, a
congenital disorder of neuronal migration, with prolonged survival,
represents a mild form of lissencephaly. It can be diagnosed during life by
computed tomography or magnetic resonance scanning.
