Interhemispheric epidermoids--an uncommon lesion in an uncommon location: a report of 15 cases

Of the intracranial epidermoids, interhemispheric epidermoids are extremely rare and only about 19 cases have been reported. This is a retrospective study of 15 patients with interhemispheric epidermoids surgically treated over a 13-year period. The age at the time of presentation varied between 17 and 45 years and there were 9 males. The presenting feature was seizures (focal with secondary generalization) in 12 patients, hemiparesis in 5 and features of raised intracranial pressure in 3. On computerized tomography scan the lesions were hypodense in the interhemispheric region. On magnetic resonance imaging, the lesions were located in the interhemispheric region with heterogenous signal intensities. Restricted diffusion was evident on diffusion-weighted images and apparent diffusion co-efficient images. All the lesions were predominantly located in the anterior interhemispheric region, with either basal or parietal extension along the interhemispheric fissure. Eleven patients underwent frontal or fronto-parietal craniotomies, 3 underwent bifrontal craniotomies and 1 patient underwent supra-orbital craniotomy and endoscopic procedure. Total excision could be achieved in 11 patients; near-total, in 3; and partial excision, in 1 patient. Follow-up was available in 10 patients. Three patients had recurrence of lesion at 5½, 8 and 10 years, respectively.