Glioneuronal migration and development disorders: histological and immunohistochemical study with a comment on evolution

Glioneuronal migration disorders of the brain evolve primarily due to aberration in neuronal migration, maturation and programming in the development of various topographic zones in the brain, following pathological alterations in glial and neuronal interactions. These are broadly referred as cortical dysplastic conditions. While these dysplastic conditions involving cerebral cortex present as drug resistant seizure disorder, those involving cerebellum present as mass lesions or slowly progressing vertigo. We report 17 cases, representing the histological spectrum of dysplastic, glioneuronal migration disorders which include, hemimegalencephaly (1), tuberous sclerosis (4), Sturge Weber Syndrome with focal dysplasia (1), Dysembryoplastic neuroepithelial tumor (7) and Lhermitte Ductos disease of cerebellum (2). The dysplastic neurons in varied stages of maturation showed neuronal cytoskeletal pathology similar to that in neuro degenerative diseases, especially when associated with cytomegaly. Similarly, cells exhibiting dual expression of glial and neuronal markers were noted in the cerebral dysplastic lesions. The dysplastic glial elements probably form the subependymal giant cell astrocytomas. Dysplastic neuronal elements form the nidus for DNT. When localized, surgical resection ameliorate the symptoms in many of these condition. Study of these conditions provide better insight into glioneuronal interaction and maturation of the brain.