[Intraparenchymal epidermoid cyst of the right frontal lobe: a case report]

Epidermoid cysts are most likely to occur at the cerebellopontine angle or in the suprasellar region. Intracerebral epidermoid cysts are rare and only 18 cases have been reported in the literature. This report presents a case of epidermoid cyst which developed in the right frontal lobe. A 24-year-old woman was admitted to our clinic on April 24, 1983 because of generalized convulsions. On admission no neurological abnormalities were found except for absence of the venous pulsation in an ophthalmoscopic study. A plain roentgenogram revealed a crescent shaped calcification in the right frontal lobe. An X-ray CT scan showed a round low density area (Hounsfield units + 12) surrounded by irregular ring-like high density spots in the right frontal lobe. Right carotid angiography showed round shift of the anterior cerebral artery to the left. The horizontal portion of the middle cerebral artery was stretched and lenticulostriate arteries were shifted laterally. Abnormal vascularization was not found. On May 11th 1983 a right fronto-temporal craniotomy was performed. Partial corticotomy was done along the cortical sulcus and the tumor was resected. The histological diagnosis was epidermoid cyst. In general an X-ray CT scan shows a low density area with irregular margin. Usually the low density area revealed -8 approximately +30 of Hounsfield units. Neither perifocal low density area nor enhancement by contrast medium is observed.