Oligodendroglial hamartoma of the right temporal lobe: a case report and discussion of possible histogenesis.

A case of oligodendroglial hamartoma is reported in a 39-year-old man with a 20-year history of petit mal seizures. Magnetic Resonance Imaging of the brain showed a small focal area of abnormal decreased signal on T1-weighted images of the right temporal lobe. The patient became seizure free after the removal of the lesion and treatment with carbamazepine. Pathologic examination revealed several aggregates of oligodendroglial cells with small, dark, regularly stained nuclei and a clear, well-defined perinuclear halo; there was no mixture of neurons or astrocytes. Although these cells were negative, the background was strongly positive for glial fibrillary acidic protein, and myelin basic protein. The histopathologic diagnosis of the temporal lobe lesion was oligodendroglial hamartoma. This report documents an additional subtype of temporal lobe hamartoma associated with seizure disorder.