Multiple unusual leptomeningeal glioneural heterotopias in a case of adult micrencephaly.

An adult patient with micrencephaly combined with unusual multiple glioneural leptomeningeal heterotopias is presented. In spite of the large number of leptomeningeal heterotopias supra- and infratentorially, the cortices of the cerebrum and the cerebellum were well-organized and the white matter was well-myelinated. The heterotopias contained glial tissue and mature neurons, those in the cerebellum resembling Purkinje cells and granular cells, along with axons and mineralizations. The pathogenesis of the leptomeningeal heterotopias and micrencephaly is discussed.