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Adrenal nodules

Last modified: January 14, 2026

Contribution from Dr. Justine Bédard (CHUS)

Main reference: ESR 2025

Secretion balance

CT C- secretion balance, ≤10U homogeneous nodule = adenoma

A dexamethasone 1mg suppression test is suggested (if not already done or depending on the patient's life expectancy/therapeutic intensity).

  

Secretion assessment for hyperplasia alone or associated with bilateral adenomas = primary bilateral macronodular adrenal hyperplasia :

  • A dexamethasone 1mg suppression test and

  • A 17-hydroxyprogesterone (17-OHP) measurement is suggested (if not already done or depending on the patient's life expectancy/therapeutic intensity)

Complete secretion assessment: If CT scan is positive or if C- >10UH = indeterminate nodule

A secretion assessment including these elements is suggested for the adrenal nodule (if not already done or depending on the patient's life expectancy/treatment intensity):

  • Dexamethasone 1mg suppression test (to be performed on a separate day from other tests)

  • Metanephrine assay (urinary OR plasma)

  • Only if hypertension or hypokalemia: add aldosterone/renin ratio measurement

Note:

  • If adrenocortical carcinoma is suspected, further tests are required, but a prompt endocrinology consultation with a call to the clinician is always suggested in this case.

  • An endocrinology consultation is not automatically required with a secretion analysis. The clinician may refer the patient if the secretion analysis is abnormal.

Important Notes

  • 1 cm minor axis for chance, but use major axis to determine the conduction

  • Nodule stability over 12 months = benign

  • >6 cm and >40 HU = suspicious lesion

  • Significant progression > 3 mm/year

  • Multiphasic CT is less relevant for the evaluation of adrenal nodules³

    • 95% of hyperverscular metastases reach the washout threshold, becoming indistinguishable from adenomas.

    • The washout threshold is not sufficiently discriminating between benign and malignant lesions.

      • In a study of 142 adrenal lesions >10HU, 43% of benign lesions did not fade and 22% of malignant lesions did fade.

Additional notes

Adrenal mass > 4 cm

Prevalence of the nature of incidental adrenal nodules

  • Adenoma and Primary bilateral macronodular adrenal hyperplasia (PBMAH) 80-85%

  • Other benign masses (myelolipoma 3-6%; other 1%)

  • Pheochromocytima (1-5%)

  • Adrenal cortical carcinoma (0.4–2%)

    • Aggressive

    • > 6 cm

    • < 4 cm 0.1%

    • 60% secreting

    • 89% asymptomatic

  • Metastases (3-7%)

    • Primary: lungs, digestive system, breast, pancreas

    • Primary unknown: very rare

Secreting lesions

  • Adenoma: 50%

  • Pheochromocytoma: 97-99%

  • Adrenal carcinoma: 60%

Figures

Figure 1. Original 2017 ACR Summary Recommendations for the Management of Incidental Adrenal Nodules

Figure 2. 2023 European Society of Endocrinology Summary Recommendations for the Investigation of Adrenal Nodules Evaluated by Non-Contrast CT

Figure 3. Graphic abstract of an article summarizing the latest data on the management of incidental adrenal nodules, published by the European Society of Radiology in 2025

References

  1. Mayo-Smith, William W., et al. “Management of Incidental Adrenal Masses: A White Paper of the ACR Incidental Findings Committee.” Journal of the American College of Radiology, vol. 14, no. 8, Aug. 2017, p. 1038–1044, https://doi.org/10.1016/j.jacr.2017.05.001.

  2. Fassnacht M, Tsagarakis S, Terzolo M, Tabarin A, Sahdev A, Newell-Price J, Pelsma I, Marina L, Lorenz K, Bancos I, Arlt W, Dekkers OM. European Society of Endocrinology clinical practice guidelines on the management of adrenal incidentalomas, in collaboration with the European Network for the Study of Adrenal Tumors. Eur J Endocrinol. 2023 Jul 20;189(1):G1-G42. doi:10.1093/ejendo/lvad066. PMID: 37318239.

  3. Seow JH, Stella DL, Welman CJ, Somasundaram AJ, Gerstenmaier JF. Washed up: the end of an era for adrenal incidentaloma CT. Insights Imaging. 2025 Jun 27;16(1):136. doi:10.1186/s13244-025-02015-4. PMID: 40579670; PMCID: PMC12204974.

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