Ultrastructural pathology of the adrenal glands in Cushing's syndrome

[Tumors of the adrenal glands : Update]

Nodular hyperplasias and adenomas are by far the most frequently resected tumors of the adrenal cortex followed by pheochromocytomas, which are either discovered incidentally or become conspicuous due to hormonal hypersecretions. Cortical nodes and adenomas are easy to diagnose using simple staining methods. Uncertain cortical carcinomas, pheochromocytomas and other tumors of the adrenal region require additional immunohistochemical staining methods. Determination of the dignity of tumors of the adrenal cortex necessitates at least the Weiss score (possibly in its modified form), for oncocytic tumors the Bisceglia score and for pediatric tumors the Wieneke score. The Ki-67 index must also be taken into consideration. For pheochromocytomas the PASS and the GAPP systeme are used.

[Effects of drugs on the adrenal cortex and its tumors]

The structure of the normal adrenal cortex is changed by stimulating hormones (ACTH) and inhibiting hormonal drugs (especially glucocorticoids). ACTH induces hyperplasia and lipid depletion in the fascicular and reticular zones, whereas glucocorticoids lead to atrophy and lipid accumulation in both zones. In animal experiments, the adrenostatic drug mitotane causes shrinkage of the cells of the fascicular and reticular zones, whereas metyrapone induces a decrease in the steroid producing organelle system and aminoglutethimide leads to an increase in lipids. In the therapy of patients with adrenocortical cancer, mitotane can cause an increase in of necrosis and fibrosis, but also in intracellular lipid. The ultrastructure shows increased liposomes, more pigment-rich lysosomes and laminated bodies.

Ultrastructural examination of the regeneration of the rat adenohypophysis after partial hypophysectomy

Male Wistar rats were partially hypophysectomized and sacrificed at intervals of from 2 days to 1 year following the operation. The resected material was examined under the light microscope and the residual pituitary under the light and electron microscope. Neither regeneration nor an anatomical restoration of the adenohypophysis occurred even one year after partial hypophysectomy. An increased number of small chromophobe stem cells and juvenile chromophil cells were found in the residual pituitary. The amount of mitoses were not significantly increased. The ACTH, FSH and prolactin producing cells demonstrated electron microscopically distinct changes which were interpreted as signs of intensified activity. This can be seen as a "functional regeneration" to maintain vital pituitary function for the organism.