THE PITUITARY IN ISOLATED ACTH DEFICIENCY - A HISTOLOGIC, IMMUNOCYTOCHEMICAL, AND IN-SITU HYBRIDIZATION STUDY

A 74-year-old man presented in a near terminal state with progressive generalized muscular weakness, gastrointestinal disturbances, and leth argy. Investigations revealed hypotension, hyponatremia, hypoglycemia, and low plasma cortisol concentration accompanied by undetectable pla sma adrenocorticotropic hormone (ACTH) level, The patient died shortly after admission to hospital, with adrenocortical failure being the pr ovisional cause of death. Autopsy disclosed profound bilateral atrophy of adrenal cortices with evidence of a mild focal inflammatory reacti on. The pituitary gland appeared normal on both gross and histologic e xaminations, There was no histologic evidence of inflammation, fibrosi s, or adenohypophysial cell hyperplasia. By immunocytochemistry, no AC TH and P-endorphin immunoreactive cells were identified in the adenohy pophysis. In situ hybridization (ISH) for pro-opiomelanocortin (POMC) mRNA yielded conclusively negative results. The case presented here wa s regarded as isolated ACTH deficiency. Although the remaining pituita ry functions were not assessed, clinical and morphologic findings stro ngly support the supposition that aside from ACTH deficiency, secretor y function of other pituitary hormones was preserved. This is the firs t case in which the pituitary was studied by immunocytochemistry and I SH. The possible pathogenetic mechanisms accounting for the isolated A CTH deficiency are discussed.