Symptomatic hydrocephalus: initial findings in brainstem gliomas not detected on computed tomographic scans.

In a retrospective review of 85 patients younger than 18 years of age with a diagnosis of brainstem glioma treated between 1974 and 1987, seven (8.3%) initially had hydrocephalus and no evidence of tumor on CT scans. Intrinsic brain tumors, six in the pons and one in the diencephalon, were discovered later, either on follow-up CT scans or on magnetic resonance images obtained despite persistently normal CT scan findings. The initial radiologic study of choice for children and adolescents with hydrocephalus should be magnetic resonance imaging, including axial and sagittal T1- and T2-weighted images. If a CT scan is obtained first and hydrocephalus but not tumor is found, magnetic resonance image should be obtained to rule out the possible presence of an intrinsic brainstem tumor.