Endocrine Abstracts

The finding of an adrenal incidentaloma warrants a careful diagnostic work-up to assess hormonal activity and potential malignancy. Current diagnostic algorithms depend largely on imaging studies, which is time-consuming, expensive and carries a health risk. Urinary steroid profiling using gas chromatography/mass spectrometry (GC/MS) might be a valuable diagnostic test for differentiating benign from malignant adrenal lesions, as adrenocortical carcinomas (ACC) often cause abnormalities in steroidogenesis. The value of this tool was retrospectively studied in 44 patients referred for analysis of an adrenal tumor or adrenal incidentaloma. The final diagnosis was histologically confirmed ACC (n=14), liposarcoma (n=1), or benign adrenal tumor (n=29). In the latter group, the diagnosis was either histologically confirmed (n=6) or based on radiological features and the absence of metastases during clinical follow-up (n=23). Patients were monitored with regular imaging studies (median follow-up 20 months, range 8–38 months). Patients were not treated with drugs interfering with adrenal steroidogenesis. The concentrations of 22 steroids were measured in 24-h urine samples. Differences in steroid metabolite excretion between patients with and without ACC were analyzed using the Mann–Whitney U test. We found that by taking the sum of four steroid metabolites (etiocholanolone, dehydroepiandrosterone, pregnanediol, tetrahydrodeoxycortisol) it was possible to distinguish ACC from other adrenal tumors with 100% sensitivity and 93% specificity. Our analysis shows that the performance of an urinary steroid profile seems to be highly predictive for differentiating benign incidentalomas from ACC. Compared to repeated radiological studies, a single urinary GC/MS at baseline has the advantages of being considerably less expensive, less time consuming and without any health risks. The diagnostic value of this tool needs to be prospectively validated.