Computerized tomography findings in pediatric patients with posterior fossa lesions.

The posterior fossa (PF) is a common site of lesions in the brain during childhood and infancy. Sixty pediatric patients with PF lesions shown on CT scans are presented. The most common lesions (48.4%) were intra-axial tumors, such as astrocytomas, medulloblastomas, and ependymomas. The tumors were relatively large at the time of diagnosis. The largest were medulloblastomas (mean maximal diameter 45.6 +/- 9.7 mm). Other abnormal findings of the PF were congenital anomalies, vascular lesions, hypoplasia and atrophy. A common approach to PF lesions is offered, emphasizing the variability, the incidence, and the different CT features of the lesions.