Risk factors and long-term follow-up of adrenal incidentalomas

The natural course of adrenal incidentalomas and the risk that such lesions evolve toward hormonal hypersecretion or malignancy are still under evalua tion. Of 246 consecutive patients with adrenal incidentaloma studied at our institution in the last 15 yr, 91 underwent surgery. Of the remaining pati ents, a group of 75 (52 females and 23 males; median age, 56 yr; range, 19- 77 yr) with incidentally discovered asymptomatic adrenal masses (60 unilate ral and 15 bilateral; median diameter, 2.5 cm; range, 1.0-5.6) was enrolled in an endocrine and morphological follow-up of at least 2 yr after diagnos is (median, 4 yr; range, 2-10). During follow-up, no patients developed mal ignancy; 9 showed mass enlargement, with appearance of a new mass in the co ntralateral gland in 2; 3 developed adrenal hyperfunction (overt Gushing's syndrome in 2, nonclinical hypercortisolism in 1); and 3 showed adrenal mas s enlargement associated with adrenal hyperfunction (nonclinical hypercorti solism in 2, pheochromocytoma in 1). The estimated cumulative risks to deve lop mass enlargement and hyperfunction were 8% and 4%, respectively, after 1 yr, 18% and 9.5% after 5 yr, and 22.8% and 9.5% after 10 yr. Nine risk fa ctors for adrenal mass enlargement or hyperfunction were arbitrarily select ed and evaluated: sex, age, presence of obesity, hypertension, diabetes, ab normal endocrine tests, mass size, mass location, and scintigraphic uptake pattern. Three of them attained statistical significance: mass size of 3 cm or more at diagnosis and exclusive radiocholesterol uptake by the mass at scintigraphy had relevance for the occurrence of adrenal hyperfunction, whe reas the presence of endocrine test abnormalities at diagnosis had predicti ve value for mass enlargement. It is concluded that subtle hormonal abnorma lities are risk factors for mass size increase, which is not a sign of mali gnant transformation. Both mass size of 3 cm or more at diagnosis and exclu sive radiocholesterol uptake, indicating higher risks of hyperfunction, sho uld be considered to plan a more thorough endocrine follow-up.