Epithelium-lined cyst of the pretectal region: case report and electron microscope study

Ultrastructural findings of an epithelium-lined cyst in the left pretectal region are reported. A 38-year-old woman developed a sensory disturbance on her right side and blurring of vision. Computed tomography scans and magnetic resonance images disclosed a round cystic lesion in the left pretectum. Light microscopically, the cyst was found to be lined by a single layer of cuboidal epithelial cells. Electron microscope examination revealed that the epithelial cells of the cyst possessed clear nuclei, abundant tonofilaments, and glycogen granules, featured as well as the usual organellae. The free surface of the epithelial cells had numerous finger-like microvilli with coating materials. These cells were interconnected by well-developed desmosomes and interdigitations, and also possessed basal lamina materials on the basal surface. These cytological features suggest a heterogenous origin of the cells rather than a neuroepithelial one.