Repeatedly reversible alteration of acoustic-evoked brainstem responses with a cystic craniopharyngioma.

The case of a cystic craniopharyngioma in a young patient, in which the tumor extended in the parasellar and retrosellar region down to the left cerebellopontine angle, is described. The postoperative reversibility of alterations in the acoustic-evoked brainstem responses after repeated surgical intervention and refilling of the cyst is described. The correlations between clinical and CT findings and the repeated alterations in the evoked responses are presented. The evoked responses were instrumental in following the postoperative course and timing CT controls. It is stressed that alterations in evoked responses were used as a reliable indication to evacuate cyst fluid via a Rickham-reservoir, although hearing was still intact, thus keeping the number of repeated CT scans lower.