Endocrine Abstracts

Incidentally discovered adrenal nodules are an increasingly common reason for referral into the endocrine clinic. Assessment includes a hormonal work-up to look for endocrine function, and reviewing the size and radiological characteristics of the lesion. Some nodules have benign radiological features (less than 10 HU on an unenhanced CT scan), whilst others are radiologically indeterminate (more than 10 HU). We worry about missing a malignant process. The research data and international guidelines may be subject to both selection bias and fee for service bias. The pre-test probability of malignancy in a patient with no known malignancy is extremely low. The history may provide clues about the possibility that the lesion represents an adrenal metastasis or an adrenal carcinoma. The size of the lesion is also helpful, with more than 4 cm being a cautious cut-off usually accepted as an indication for surgery, and sub-centimetre lesions probably not requiring any further follow-up. A dedicated adrenal CT scan with wash out sequences, and a review of the radiological characteristics of the lesion with a specialist radiologist as part of an MDT assessment, is recommended. There is less evidence at present to support the use of other diagnostic tests in most situations. Growth on follow-up imaging increases the likelihood of malignancy, but this has to be balanced against the risks of radiation exposure and the opportunity cost for the NHS. Patient preference, co-morbidities and frailty will also influence management plans. For radiologically indeterminate non-functioning adrenal nodules, a pragmatic approach to follow-up could include a dedicated adrenal CT scan with wash out sequences, then (if the lesion is still radiologically indeterminate) two follow-up adrenal scans over a 2 year interval from the initial imaging (non-contrast CT, or MRI in under 40s), before the patient is discharged if the lesion remains stable.