Temporal soft tissue glioneuronal heterotopia in a child with a seizure disorder: case report and review of the literature.

Tissue and cellular elements generally attributed to the central nervous system (CNS) are infrequently found in areas outside the CNS proper. Most of these lesions contain predominantly glial tissue. In rare instances, heterotopic CNS tissue is found in the scalp, many associated with an intracranial connection and overlying skin and hair anomalies. In follow-up of these patients, development is normal. We present a case of a temporal scalp mass in a 19-month-old girl with a seizure disorder beginning at about age 1 year. At the time of excision, the mass was not associated with intracranial connection or overlying cutaneous abnormalities and demonstrated abundant neuronal and glial elements with features of dysplastic CNS tissue. We speculate that, in certain circumstances, aberrantly localized CNS tissue may be related to abnormal CNS development.