[Epithelial cysts of the central nervous system: report of two cases].

Two cases of epithelial cyst are reported. Case 1. A 68-year-old female visited our hospital with a complaint of decreased visual acuity, 0.04 in the left eye, in September 1986. Visual field examination showed bitemporal hemianopsia. CT scan demonstrated nonenhancing cystic lesion involving the suprasellar region. By a right frontotemporal craniotomy, the suprasellar cyst was explored. The wall of the cyst was partially removed to relieve pressure against both optic nerves and chiasma. Histologically, the cyst wall was lined with a single layer of non-ciliated cuboidal epithelium. Electron microscopic study revealed a number of microvilli, continuous basement membrane and desmosomes. Case 2. A 40-year-old female was admitted to our hospital because of sensory disturbance in the left hand for several years. She had an episode of convulsive seizure with a loss of consciousness. Neurological examination revealed hypesthesia of the left hand. CT scan showed non-enhancing right frontoparietal cystic lesion compressing the right lateral ventricle to the left. By a right frontoparietal craniotomy, the cystic lesion was explored. The cyst existed beneath an arachnoid membrane and contained CSF-like clear fluid. The cyst wall was resected, as far as possible, to obtain communication with normal subarachnoid CSF space. Histologically, by light and electron microscopic study, the cyst was considered to be an epithelial cyst. A correct diagnosis is difficult because other cystic lesions such as arachnoid cysts and craniopharyngioma are of similar low density and appear the same on CT scan. It is impossible to diagnose such an epithelial cyst by relying on neuroradiological study alone.(ABSTRACT TRUNCATED AT 250 WORDS)