[Clinical aspect of adrenal incidentaloma]

Adrenal incidentaloma is defined as clinically inapparent adrenal mass identified at abdominal imagine undertaken for health screening or examination of unrelated diseases. Recent national Survey by Research Committee of Japanese Ministry of Health and Labor revealed 2,016 cases of adrenal incidentaloma in year 1999. Analysis of 2,626 cases including additional new cases indicate 51% was non-functional adrenocortical adenoma, cortisol producing adenoma 8.9%, pheochromocytoma 8.5%, aldosteronoma 4.2%, adrenal cancer 1.4%. Cut of point for cancer was estimated at 5 cm. 1 mg dexamethasone test and circadian rhythm of cortisol secretion evaluation may be necessary for exclusion of clinically inapparent cortisol producing adrenal adenoma known as preclinical Cushing's syndrome. Clinical aspect and management of adrenal incidentaloma was briefly reviewed based on this national report.