The Prevalence of Incidental Adrenal Mass Found Using Diagnostic Imaging Techniques

ABSTRACT

Purpose: Incidentally-found adrenal masses detected by imaging studies performed for unrelated reasons have become more common in the clinical practice. Our study aims to assess the nature and prevalence of incidental adrenal masses discovered on CT or MRI in patients without malignancy.
Material and Method: We analyzed the reports of 8378 abdomen or chest CT and 820 abdominal MRI examinations performed on 4973 patients in our hospital. We found 629 (12.6%) incidental adrenal masses. We excluded 194 (3.9%) patients with known cancer or high-risk adrenal metastasis. The remaining 435 (8.7%) adrenal masses constituted the study group. This group consisted of 274 (5.9%) patients [123 (44.9%) women and 151 (55.1%) men] with masses greater than 1 cm in diameter and 161 (2.8%) patients with masses less than 1 cm.
Results: The mean age of the patients was 62.55±13.23 years. Unilateral adenoma was the most common type of adrenal masses (n=112, 40.9%). Less commonly observed adrenal masses were: unilateral [n=79 (28.8%)] and bilateral [n=35 (12.8%)] macronodular hyperplasia, unilateral [n=33 (12%)] and bilateral [n=2 (0.7%)] diffuse adrenal thickness, bilateral adenoma [n=7 (2.6)], unilateral [n=3 (1.1%)] and bilateral [n=3 (1.1%)] micronodular hyperplasia. The masses were most commonly found in the left adrenal gland (165, 60.2%). They were found at lower rates in the right adrenal gland (66, 24.1%) and bilateral adrenal glands (43, 15.7%). The mean sizes of left and right adrenal masses were 1.89±1.11 cm and 2.02±0.86 cm, respectively.
Discussion: Patients harbouring adrenal incidentalomas should be evaluated for the possibility of malignancy and/or hormone activity. The lack of controlled studies impedes specific management and recommendations for adrenal incidentalomas. Large prospective controlled studies on this topic are needed.