The Incidental Adrenal Mass on Computed Tomography

Abstract

Background: The widespread use of computed tomography (CT) has resulted in the frequent incidental discovery of asymptomatic adrenal masses. The aim of the present study was to report retrospectively a 4-year CT studies of the frequency of adrenal incidentalomas (AI) in a tightly defined geographical area in Jeddah, Saudi Arabia. Design: This retrospective study was approved by our institutional review board, and informed consent was waived. The CT reports of 15,600 abdominal CT examinations from our institution at King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia performed from January 2015 to December 2018 were searched for the word “adrenal” in the impression. The search identified 87 patients with adrenal lesions which constituted the subject material for the study. Results: During a 4-year period, a total of 87(0.6%) patients were diagnosed with AI and included in the study. Demographic characteristics were as follows: 37 (43%) males and 50 (58%) females, aged between 30–87 years (median, 58 years and mean ± SD 58.7±13.6 years). Fifty-five percent of the subjects were in their 50s and 60s. AI in males were more frequent in the fourth, eighth and ninth decades whereas AI in females were more frequent in fifth and seventh decades. AI were more frequent on the left [47 (54%)] than on the right side [28 (32.3%)], whereas bilateral AI were found in 12 [(13.8 %)] patients. Moreover, AI in males were more frequent on the right [17 (45.9%)] than on the left side [11 (22.0%)], whereas AI in females were more frequent on the left 15 (40.5%) than on the right side 32 (64.0%) and slightly more frequent in bilateral sites (14% vs. 13.5%), p=0.05. The size of the right-sided AI (1.9±1.3 cm) were non-significantly larger than the left-sided ones (1.6±0.8 cm), p=0.2.In the overall series, the diameter of the AI estimated by CT ranged from 0.5–7.9 cm; (median, 1.7 cm and mean 1.8±1.1 cm) where the largest number of patients with AI were seen in 8 cases (11.7%) at size of 1.7 cm. Most lesions [60 cases (69%)] were less than 2.0 cm, whereas the mean size of bilateral AI in the dominant mass (2.3 cm) was larger than mean size of right (1.9 cm) or left (1.6 cm) AI. The frequency of AI more than 4 cm was higher in the right side (50%) and the dominant mass in the bilateral AI (50%) within the size of AI groups whereas the frequency of AI less than 2 cm was higher in the right side of AI (57%). The mean size of AI was larger in the sixth decade compared to other age groups whereas males (2.1 cm) and females (2.7 cm) have higher mean size of AI in the fourth and sixth decade respectively. A negative non-statistically significant correlation was found between age and mass size (r= 0.132, p=0.2). In addition, a positive non-statistically significant correlation was found between BMI and AI size (r= 0.066, p=0.6). Conclusion: In conclusion, the current study indicated low prevalence of AI as indicated by CT. In the absence of registry data, larger cooperative studies involving diverse population samples from multiple centers could help to provide further information on the true frequency nationally.