The main problem in the management of the patients with incidentally discovered adrenal mass (incidentaloma) is whether and when the incidental mass puts the patient at increased risk for an adverse outcome. As osteoporosis is a well known complication of endogenous and exogenous glucocorticoid excess, it is likely that patients with incidentally discovered adrenocortical adenomas have impaired bone mass due to subclinical hypercortisolism. We measured spinal bone mineral density (BMD) by dual energy x-ray absorptiometry in 27 patients (9 men and 18 women) and 54 healthy subjects (18 men and 36 women) carefully matched for age, sex, body mass index, and menstrual status for a case-control analysis. BMD was also measured at the hip in the group of patients. A multiple regression analysis was performed to determine which biochemical variables might influence BMD values. Lumbar BMD values in patients with adrenal incidentaloma were not significantly different from those in control subjects (BMD, 0.926, 0.604--1.144 vs. 0.936, 0.645--1.268 g/cm(2); P = NS). No significant difference in lumbar and femoral BMD was found between patients with or without subclinical Cushing's syndrome. Among the variables processed, only PTH remained in the final model and was inversely correlated with lumbar spine and femoral neck BMD values (r = -0.5; r(2) = 0.25; P = 0.015 and r = -0.42; r(2) = 0.18; P = 0.03, respectively). In conclusion, our data do not suggest that the slight glucocorticoid excess associated with adrenal incidentaloma increases the risk of osteoporosis. The evaluation of BMD does not seem to be crucial in the management of incidentally discovered adrenal masses.