Three patients with symptoms of headache and vision loss had normal routine CAT scans, with and without injection of contrast medium, as their initial diagnostic procedure. Subsequent pneumoencephalography revealed large suprasellar masses, which at operation were found to be partially cystic craniopharyngiomas. The findings emphasize the existence of craniopharyngiomas that are isodense with brain and may not be detected on routine CAT scan. When a patient's clinical presentation suggests chiasmal or sellar abnormalities, the pneumoencephalogram remains the most accurate diagnostic procedure.
