Preclinical cushing’s syndrome: Report of four cases and analysis of steroid contents in adenomas

We report 4 cases of preclinical Cushing’s syndrome (PCS) that were discovered incidentally by computed tomography (CT) as adrenal incidentalomas. Routine endocrine examinations revealed a suppressed plasma ACTH level. A final diagnosis was made by means of precise endocrine assessments and adrenal scintigraphy with radiolabelled iodocholesterol. Although endocrine data varied, the positive accumulation of radioisotope in the adrenal tumor, with nonvisualization of the contralateral side, was observed in all cases. Endocrine studies and analyses of steroid contents in tumors by HPLC suggested that subtypes or heterogenous forms of this disease entity may exist. One type shows small tumors with relatively elevated cortisol production, and a disturbed diurnal rhythm and suppression of plasma cortisol with dexamethasone (DXM). The other type showed large tumors with weak-to-average cortisol production, and the diurnal rhythm of cortisol was preserved.