Gonadotroph adenomas of the human pituitary: sex-related fine-structural dichotomy. A histologic, immunocytochemical, and electron-microscopic study of 30 tumors.

Thirty pituitary tumors, removed from 14 men and 15 women, were diagnosed as gonadotroph adenomas on the basis of their immunocytochemical and/or ultrastructural features. Serum follicle-stimulating hormone (FSH), but not luteinizing hormone (LH), was elevated in 8 men, whereas none of the women had gonadotropin levels, as measured by radioimmunoassay, inappropriately high for their age. Immunoreactive FSH (sometimes also LH) was present in 13 of 15 tumors in men but only 6 of 13 adenomas in women. By electron microscopy, gonadotroph adenomas in men had uncharacteristic features often similar to those of null-cell adenomas with poorly or moderately developed cytoplasmic organelles. In women, all tumors were well differentiated, with a highly distinctive vesicular dilatation of the Golgi complex ("honeycomb Golgi") as a diagnostic marker present in 14 of 15 adenomas. To the author's knowledge, this is the first example of sex-linked dichotomy within a tumor type expressed as the markedly different ultrastructural appearance of cytoplasmic organelles, especially the Golgi apparatus.