Clinical Characteristics and Follow-Up Results of Adrenal Incidentaloma

It is recommended that adrenal incidentaloma patients should be monitored for radiological changes, increase in size and new functionality that may occur in the future, even if they are benign and nonfunctional at the initial evaluation. Our aim is to evaluate the key clinical characteristics of adrenal incidentaloma patients focusing on changes during follow-up and associated clinical outcomes. A total of 755 patients (median age: 56 years), with an adrenal incidentaloma > 1 cm and underwent functionality tests, were included in the study. Clinical characteristics, functionality status and follow-up durations were recorded. During the course of follow-up, any changes in size and development of new functionality, and clinical consequences thereof were evaluated. In 71.8% of patients, incidentalomas were non-functional. Most frequent functionality (15.8%, n=119) was subclinical hypercortisolemia (SH) [10.9% (n=82) possible autonomous cortisol secretion (PACS) and 4.9% (n=37) autonomous cortisol secretion (ACS)] of all incidentalomas. Frequencies of Cushing's syndrome (CS), pheochromacytoma and primary hyperaldosteronism were 4.9% (n=37), 3.8% (n=29) and 3.7% (n=28), respectively. Adrenocortical carcinoma frequency was 1.5% (n=11). Of 755 patients, 43% (n=325) were followed up regularly more than 6 months. Median follow-up duration was 24 months (6-120). A total of 17 (5.2%) patients, which had non-functional incidentalomas at baseline had developed new functionality during follow-up, of which 15 (4.6%) were SH [13 patients (4%) PACS and 2 patients (0.6%) ACS] and 2 (0.6%) were CS. During follow-up, 24% (n=78) of the patients had an increase in mass size between 5-9 mm, while 11.7% (n=38) of the patients had an increase of ≥10 mm. During follow-up, 4% (n=13) of the patients developed a new lesion with a diameter ≥10 mm on the opposite side. In patients with a follow-up duration of more than 2 years, frequencies of size increase and new lesion emerging at the opposite adrenal gland were higher. 14 patients (4.3% of the patients with regular follow-up) underwent surgery due to increase in size or development of new functionality during follow-up. Our study demonstrated that a necessity for surgery may arise due to increase in size and development of functionality during follow-up period in adrenal incidentaloma patients, and thus continuing patient follow-up, even with wider intervals, will be appropriate.