SIMPLE NUMERICAL CHROMOSOME-ABERRATIONS IN 2 PITUITARY-ADENOMAS

Cytogenetic analysis of short-term cultures of one non-secreting and one prolactin-producing pituitary adenoma revealed simple clonal numerical abnormalities in both tumors. The karyotype of the non-secreting adenoma was 48,XX, + 4, + 9[42]/49,XX, + 4, + 9, + 20[2]/46,XX[6]. In the prolactin-secreting adenoma, three aberrant clones were detected, giving the karyotype 45,X, - Y [20]/47,XY, +Y[6]/45,XY, - 21[3]/46,XY[21]. One cell had the chromosome complement 46.X, - Y, + 9; no other nonclonal aberrations were detected. The only hitherto published case of pituitary adenoma analyzed by banding techniques (Rey et al. [1986]: Cancer Genet Cytogenet 23:171-174) also had only numerical clonal changes that included extra copies of chromosome 9. We conclude that pituitary adenomas may be karyotypically characterized by numerical aberrations and that trisomy 9 seems to be the best candidate for a primary chromosomal anomaly.