Heterotopic gray matter in white matter in a 62 year old

Abstract

“Heterotopia” describes normal cells in an abnormal location, and in the context of neurobiology, usually refers to neurons or gray matter in the leptomeninges or in periventricular or subcortical white matter, (“Gray Matter Heterotopia”). While once thought to be quite rare, the widespread MRI availability allowed increased recognition of these malformations. Clinically, gray matter heterotopias usually manifest as seizures in the first and second decades of life and may have associated motor and cognitive developmental disturbances. We report a patient with no known prior neurologic history, who developed seizures at the age of 62, which were subsequently determined to be from a subcortical gray matter heterotopia. The patient presented to an outside hospital with episodic confusion thought to represent partial seizures, and also numbness in her left foot, leg, and arm. MRI revealed a thickened corpus callosum and abnormal signal extending into the right cingulate gyrus white matter with an infiltrative appearance suggestive of a glioma or gliomatosis. Stereotactic biopsy demonstrated white matter containing irregular islands of synaptophysin-immunopositive gray matter within which there were large dysplastic neurons. This established a diagnosis of ectopic gray matter in the subcortical white matter. To our knowledge, this is the oldest age at which a person with this congenital condition has experienced onset of related symptoms.