Does the corticoadrenal adenoma with "pre-Cushing's syndrome" exist?

An adrenal tumor was discovered fortuitously in a patient with no clinical features of Cushing's syndrome. On adrenal imaging, there was good uptake in the nodule but no visualization of the contralateral adrenal. The latter was seen, however, in a second scan performed under ACTH treatment. In the hormone assessment, basal cortisol and 17-hydroxycorticoids were normal and cortisol diurnal variation was near normal, but a dexamethasone suppression test and ACTH responses to metyrapone and insulin hypoglycemia were abnormal. Eight months after excision of a spongiocytic-type adenoma, the remaining adrenal was visible on scintigram and the hormonal tests were normal. This pattern suggests that the clinical Cushing's syndrome but enough to suppress partially ACTH and, consequently, visualization of the contralateral gland.