Evaluation of incidental adrenal mass

Incidental adrenal masses are typically found during radiologic imaging of kidneys and adrenals. They are classified as hormonally active or nonfunctioning, and as malignant or benign.

The prevalence of clinically inapparent adrenal masses increases with age, being <1% for patients younger than 30 years of age and increasing to 7% in patients 70 years of age and older.[1]Grumbach MM, Biller BM, Braunstein GD, et al. Management of the clinically inapparent adrenal mass ("incidentaloma"). Ann Intern Med. 2003 Mar 4;138(5):424-9. http://www.annals.org/cgi/content/full/138/5/424 http://www.ncbi.nlm.nih.gov/pubmed/12614096?tool=bestpractice.com

Forty-one percent of incidental adrenal masses are adenomas, 19% metastases, 10% adrenocortical carcinomas, 9% myelolipomas, up to 8% pheochromocytomas, and the remainder mostly benign tumors (cysts, adrenolipomas, hematomas, leiomyomas, lymphangiomas).[2]Agency for Healthcare Research and Quality. Management of clinically inapparent adrenal mass. Evidence Report/Technology Assessment: No. 56 AHRQ Publication No. 02-E013. February 2002 [internet publication]. http://archive.ahrq.gov/clinic/tp/adrentp.htm [3]Kloos RT, Gross MD, Francis IR, et al. Incidentally discovered adrenal masses. Endocr Rev. 1995 Aug;16(4):460-84. http://www.ncbi.nlm.nih.gov/pubmed/8521790?tool=bestpractice.com

The prevalence of adrenal adenoma is 6% based on autopsy studies, and 4% based on abdominal computed tomography.[4]Young WF Jr. Clinical practice. The incidentally discovered adrenal mass. N Engl J Med. 2007;356:601-10. http://www.ncbi.nlm.nih.gov/pubmed/17287480?tool=bestpractice.com

Most hormonally active adrenal tumors causing Cushing syndrome, pheochromocytoma, or primary hyperaldosteronism are benign, but uncommonly they may be malignant.

Adrenocortical carcinoma, while rare, is frequently hormonally active.