FEMINIZING tumors of the adrenal cortex are associated with symptoms that presumably reflect the combined effects of estrogen excess and androgen deficiency — gynecomastia, diminished libido, attenuated potency, and testicular and prostatic atrophy.1 2 3 4 5 Although such tumors are extremely rare, they provide a unique opportunity to appraise the nature of endogenous estrogen action on the gonadal axis in men. In principle, the pathophysiologic effects of estrogen hypersecretion could be expressed at the level of either the Leydig cell or the hypothalamic–pituitary axis (or both), with consequent suppression of androgen production. In the present studies, we investigated the endocrine consequences of reversible endogenous estrogen excess in a patient with a surgically resectable feminizing adrenal cortical tumor
