抄録
A case of an epithelial cyst of the fourth ventricle is reported. A 10-month-old girl was admitted because of inactivity, developmental retardation, and enlarged head. On admission she was inactive and the head circumference measured 48.5 cm with tense fontanel and dilatation of scalp veins. Neurological examination showed a slight hyperreflexia in both lower limbs. Computerized tomography scan disclosed a large round low density area in the region of the fourth ventricle and marked dilatation of the third and lateral ventricles. Suboccipital craniectomy was performed and a 4 cm diameter cyst within the fourth ventricle was totally removed. The cyst contained watery clear fluid. On light microscopic examination, the cyst wall was composed of a single layer of columnar or cuboidal epithelial cells and thick collagenous connective tissue. Electronmicroscopic study revealed that the epithelial cells rested on a basement membrane separating them from the underlying collagenous tissue. Cilia and microvilli without coating material were occasionally present on the surface of the cells.
The literature is reviewed and the origin of the cyst is discussed. The authors suggest that the cyst originated from the developing choroid plexus.
