Atretic cephalocele appears as an unimportant and benign lesion. This malformation consists of meningeal and vestigial tissues (arachnoid, glial, or central nervous system rests). The authors report the findings in 16 cases (seven parietal and nine occipital) of rudimentary cephaloceles. Twelve patients presented with associated brain abnormalities detected by either computerized tomography (CT) or magnetic resonance imaging (MR). Nine lesions also exhibited an anomalous vascular component demonstrated by CT or MR imaging or at surgery. The existence of this tiny malformation in five cases was the main diagnostic clue to a severe complex of cerebral anomalies, namely cerebro-oculomuscular (Walker-Warburg) syndrome. An occipital location of the atretic cephalocele was associated with the worst prognosis, with only two children developing normally. However, a parietal location carried a better prognosis, which is contrary to the outcome reported in the current literature. The authors classify atretic cephaloceles into two types based on histological examination of the surgical specimens, and suggest that these types represent different stages in the development of this malformation. It is concluded that, in the evaluation of the atretic cephalocele, the neurosurgeon is obliged to proceed to a detailed neuroradiological study of the patient and that the prognosis does not depend on the existence of the cephalocele itself, but rather on associated "occult" brain anomalies.