yttrium-silicate and Pituitary-Neoplasms

Radiosurgery, using 90Y injected directly into the cavity of cystic craniopharyngiomas produces remarkable reduction of tumour size and diminishes cyst fluid production. The authors have studied the histology of biopsy and autopsy material obtained from seven patients presented with cystic craniopharyngiomas. Histological examination was carried out before and after 90Y silicate implantation. As an effect of 90Y irradiation, histology of samples taken from the cyst wall revealed that the lining epithelial cell layer became destroyed and the cyst wall shrunk. Large amount of collagen fibres with focal hyaline degeneration was present. Proliferation of intimal cells and subendothelial connective tissue narrowing small vessel lumina also occurred. Considering that fibrotic tissue is more susceptible to shrink, the fibrosis induced by irradiation together with destruction of the squamous epithelium and vascular changes, might explain the reduction of the cyst volume and diminished fluid secretion after 90Y treatment.

Topics: Brachytherapy; Combined Modality Therapy; Craniopharyngioma; Cysts; Humans; Hyalin; Pituitary Neoplasms; Silicates; Silicic Acid; Silicon Dioxide; Yttrium; Yttrium Radioisotopes

The authors describe the intracavital treatment with 90Y silicate colloid in 9 cases of cystic craniopharyngioma. The method has been applied since 1975 in the National Institute of Neurosurgery, Budapest. The intracavital treatment was only one among several applied treatment forms. In all patients a partial removal of the tumour has also been performed. The possibilities of evaluation of the effectiveness of the internal cyst irradiation are therefore limited. In most cases the intracavital treatment resulted in shrinkage of the cyst, or even was followed by its practical disappearence and the condition of the patients shows a decisive improvement. The growth of solid tumour parts is not influenced by this kind of treatment. Therefore the clinical improvement of the patient's condition depends also on the ratio between cyst and solid tumour volume. The optic nerve impairment did not improve in all cases. As a side-effect an oculomotor nerve paresis developed in several patients. Its possible explanations have been discussed, including lasting damage from tumour pressure.

Topics: Adolescent; Adult; Brachytherapy; Child; Combined Modality Therapy; Craniopharyngioma; Cysts; Female; Humans; Male; Neoplasm Recurrence, Local; Pituitary Neoplasms; Silicates; Tomography, X-Ray Computed; Yttrium; Yttrium Radioisotopes