[Clinical value of tumor size in the evaluation of adrenal incidentalomas]

Objective: To investigate the clinical value of tumor size in the evaluation of endocrinological and histological natures regarding adrenal incidentaloma (AI) patients. Methods: A total of 1 941 AI patients who were hospitalized in Department of Endocrinology, Chinese PLA General Hospital between January 1997 and December 2016 were retrospectively reviewed. The demographics of patients, imaging features, functional status and histological results were analyzed. Results: Of 1 941 patients, 984 (50.70%) were males, and 957 (49.30%) were females. The median age was 52 years old. Endocrine evaluation according to the mass size showed that the proportion of non-functional AI and primary aldosteronism (PA) was declined from 84.55% (558/660) to 27.95% (45/161) and from 6.82% (45/660) to 0, respectively. The highest frequency of subclinical Cushing's syndrome (SCS), PA and pheochromocytomas were observed in 2.1-4.0, ≤2.0 and 4.0-6.0 cm group, respectively. Histological results showed that in>6 cm group, the frequency of malignancy were sharply increased. Multivariate logistical regression analysis indicated tumor size had a significant association with the presence of malignancy (OR=1.043, 95% CI: 1.033-1.054, P<0.001). A mass size of 4.0 cm was of great value in distinguishing malignant tumors from the benign ones, with a sensitivity of 89.19%, and a specificity of 69.91%. Conclusion: Mass size was of great value in the endocrinological evaluation, as well as distinguishing malignant tumors from the benign ones in AI patients.