A nationwide survey of adrenal incidentalomas in Japan: the first report of clinical and epidemiological features

Abstract

The aim of this study was to reveal clear epidemiologic and clinical characteristics of incidentally discovered adrenal masses, termed adrenal incidentalomas (AIs), and to establish appropriate managemental and therapeutic regimens in Japan. This study had been originally carried out as a project of a research proposed on behalf of the Japanese Ministry of Health, Labour and Welfare, from 1999 to 2004. This nationwide multicenter study on AIs included 3,672 cases with clinically diagnosed AIs, involving 1,874 males and 1,738 females, with mean age 58.1 ± 13.0 years (mean ± SD). In the present study, we focused on the investigation of the real prevalence of various adrenal disorders with AI. The mean nodule size of AI based on computed tomography was 3.0 ± 2.0 cm. Compared to non-functioning adenomas (NFAs), tumor diameters were significantly larger in adrenocortical carcinomas (ACCs), pheochromocytomas, cortisol-producing adenomas (CPAs), myelolipomas, metastatic tumors, cysts, and ganglioneuromas (p < 0.01). Endocrinological evaluations demonstrated that 50.8% of total AIs were non-functioning adenomas, while 10.5%, including 3.6% with subclinical Cushing's syndrome, were reported as CPAs, 8.5% as pheochromocytomas, and 5.1% as aldosterone-producing adenomas. ACCs were accounted for 1.4% (50 cases) among our series of AIs. In conclusion, while almost 50 % of AIs are non-functional adenomas, we must be particularly careful as AIs include pheochromocytomas or adrenal carcinomas, because they may be asymptomatic. To our knowledge, this is the first and the largest investigation of AI, thus providing basic information for the establishment of clinical guidelines for the management of AI.

Presentation and outcomes of adrenal ganglioneuromas: A cohort study and a systematic review of literature

“…Of these, 85 were selected for 2. 4,[8][9][10][11]14,[20][21][22][23][24][25][26][27] The majority were retrospective cohort studies, with one being cross sectional. Most were conducted in China (n = 7).…”

Discrepancies in the Recommended Management of Adrenal Incidentalomas by Various Guidelines

“…6,7 A recent, large epidemiological study supports the existing literature that the majority of adrenal incidentalomas are in fact nonfunctioning adenomas. 8 At a cutoff of 10 HU the sensitivity of unenhanced CT in predicting an adenoma is around 71% and the specificity is 98%. 9,10 Given the high incidence of adenoma and the high specificity of CT in identifying adenoma, unenhanced CT is an adequate first line screening test.…”

“…20 In fact, subclinical Cushing syndrome is the most common hormonal dysfunction caused by AIs. 8 This is usually defined as abnormal dexamethasone suppression screening results, without overt signs or symptoms of cortisol excess, and variable confirmatory testing with other measurements of cortisol production. In the case of abnormal dexamethasone suppression testing without other evidence for cortisol excess patient preference and severity of comorbidities should be taken into account for shared decision making on surgery vs conservative management.…”

Presentation, disease progression and outcomes of adrenal gland metastases

“…Adrenal tumours are reported in 4.4%‐7.3% of adults, where most represent benign adenomas 1‐3 . Adrenal malignancies represent only 2.8%‐6.7% of all adrenal tumours, with the prevalence of adrenal cortical carcinomas around 0.6%‐3.7% and the prevalence of adrenal gland metastases around 0.5%‐3.8% 4‐6 . Patients with a newly discovered adrenal tumour should undergo evaluation to assess if the tumour is malignant and/or hormonally active 7 .…”