CYTOGENETIC FINDINGS IN PITUITARY-ADENOMA - RESULTS OF A PILOT-STUDY

Pituitary adenomas are the most common tumors of the sellar region and are, with rare exception, benign neoplasms. The natural history of th ese lesions is only poorly understood and, although histologic, immuno cytologic, and ultrastructural characteristics have been well establis hed, predicting the natural history of individual tumors is, at best, unreliable. In an effort to better characterize pituitary adenomas, we have analyzed the karyotypes of 18 surgical specimens and attempted t o correlate with the morphologic appearance and the clinical data, for example, endocrinologic subtypes, histology, and tumor invasiveness. Most hormonal subtypes were studied including seven growth hormone-pro lactin (GH-PRL), two Prolactin (PRL), two Adrenocorticotrophin (ACTH), seven nonsecretory (NULL). No correlations with morphology or invasiv eness could be made. Of 7 null cell adenomas, five (71%) had normal ka ryotypes, whereas of 11 hormone-secreting adenomas three (28%) were no rmal. Of seven tumors with mixed GH-PRL activity, six had abnormal kar yotypes. At least three chromosomes harbored abnormalities shared by m ore than two tumors. The results demonstrate that chromosome abnormali ties are also found in benign tumors. These findings, however, suggest that hormone-secreting adenomas may be more likely to be associated w ith karyotypic abnormalities especially those of the GH-PRL variety. G enetic abnormalities associated with chromosomes 1, 4, 7, and 19 were common and warrant further investigation.