[Intracystic instillation of yttrium 90 silicate colloid in cystic craniopharyngioma].

The authors evaluate the intracavital treatment with 90 Yttrium silicate colloid given in 31 occasion in 26 patients of cystic craniopharyngioma. The method has been applied since 1975 in the National Institute of Neurosurgery Budapest, using practically the same method as described by Backlund et al. (1972). Although the intracavital treatment was only one among several applied forms of treatment (resection, aspiration, shunting etc.) the effectiveness of the internal irradiation is obvious. The main effect is shrinkage of the cyst. At the 26 patients there was an average of more than 70% volume decrease of the cysts. In 5 cases the cysts totally disappeared and only on two occasions the volume has remained unchanged. Neuroophtalmological data: Preoperatively visual field defects or an impairment of visual activity have been observed in 24 out of the 26 patients studied. After the 90-Yttrium treatment the ophtalmological state of the patients improved 4, worsened in 2 cases. There was no change in 18 cases. The neuroophtalmological prognosis was good only when a relatively intact optic disc was seen; when the disc was atrophic the visual deterioration proved to be irreversible. Pathologically, the fibrotic tissue is responsible for the shrinkage of the cyst.