Pearl in interhemispheric fissure: A rare phenomenon.

Epidermoid cysts (Keratin pearls) are benign congenital lesions, found commonly in cerebello-pontine angle, suprasellar cistern, sylvian cistern, pineal region, but they are very rare in interhemispheric fissure. Approaching these lesions are challenging to neurosurgeons because of narrow and deep fissure with surrounding vital structures. The present study constitutes an analysis of interhemispheric epidermoid managed at our hospital in last 10 years (Jan 2001-Dec 2010). Total 187 cases of intracranial epidermoid operated in our institute; eight of them were interhemispheric epidermoid making about 4.27% of all epidermoids. The patients were presented with seizures (50%), headache (37%), and weakness (25%). On examination, the common findings were decreased Mini mental score (MMSE) in 50%, motor deficit in 25%, and decreased visual acuity in 25% of cases. All patients underwent craniotomy across the midline as per the location of the lesions. In seven patients, tumors were resected by interhemispheric approach but in one by transcortical. Lesion were excised with microscope and endoscopic assistance with measures to prevent spillage of epidermoid tissue while excision. Post excision tumor bed was irrigated with hydrocortisone diluted saline. All patients except one improved after surgery and non-developed chemical meningitis. One patient of parietal interhemispheric epidermoid with transcortical approach developed weakness in immediate post-operative period. Patients were followed for average 6.8 year without any recurrence. Interhemispheric epidermoids are rare tumors. Achieving safe complete excision without spillage is surgical goal to prevent chemical meningitis and recurrence. Endoscope assists in achieving complete excision so decrease incidence of chemical meningitis and recurrence.