Licht- und elektronenoptische Untersuchungen zur sekretorischen Aktivität von Hypophysenadenomen bei Akromegalie

Eleven pituitary adenomas in patients with acromegaly were examined with special reference to their secretory activity. The adenomas with high secretion of growth hormone were histologically characterized by well-developed vascularization, sparsely acidophilic granulation of the cytoplasm, and pleomorphism of the nuclei. Ultrastructural findings were a well-developed rough-surfaced endoplasmatic reticulum, a large, double Golgi-complex, relatively densely packed cytoplasmatic organellas, more immature than mature secretory granules, and only a few products of granule-degradation. Two adenomas showed signs of high activity histologically only but this was not confirmed by ultrastructural examination. The two were recurrent adenomas; therefore we suppose that pleomorphism of the nuclei in association with an increased number of mitoses must be interpreted as sign of increased rate of tumor growth and not of secretory activity. Comparison of the morphological degree of secretory activity with the preoperative plasma level of growth hormone yielded a good degree of correlation in 9 of 10 cases.