Colloid cyst of the fourth ventricle: diagnostic problems and pathogenic considerations.

The authors report the case history of a patient with a colloid cyst of the 4th ventricle. The clinical history of slow intracranial hypertension, homogeneous hyperdensity with contrast enhancement on computed tomographic, scan, and the gelatinous aspect of the cyst at surgery are characteristic of colloid cysts. The diagnosis was made, however, only at the time of histological examination. A common neuroepithelial origin with 3rd ventricle cysts would be explained by similar embryological developments of the prosencephalic and the rhombencephalic roofs.