Endocrine Abstracts

Objective: Incidentally discovered adrenal masses (‘incidentalomas’) are found in 2% of the population. Adrenalectomy is necessary only in a small proportion of such subjects as outlined by the relevant ESE/ENSAT guideline¹. However, uncertainty exists over the need for removal of lesions between 4 and 6 cm and those with low lipid content on CT scanning (found in 20% of benign adenomas). Our centre tends to offer surgery for all adenomas >4 cm.

Method: We scrutinised our adrenal surgical database for all patients who had undergone adrenalectomy due to size > 4 cm, imaging characteristics not typical of benignity (low lipid content) or growth velocity >20% over 12 months¹. We then examined subsequent adrenal histology with original indication for surgery.

Results: Ninety-seven patients with incidentalomas > 1 cm were identified between 2009 and 2017. Patients with malignant disease and/or hormone excess (n=48) were excluded. The remaining 49 patients underwent adrenalectomy for criteria outlined above. The majority of excised lesions were benign cortical adenomas (38; 78%). Of the eight malignant adenomas, five were adrenocortical carcinoma, as well as a sarcoma, hepatocellular carcinoma and the other ‘unclear’. Three tumours were histologically classified as phaeochromocytoma despite being biochemically silent. If the size threshold had been increased to >6 cm, removal of benign lesions is reduced by 39%.

Discussion: In our series of 49 subjects who underwent adrenalectomy, only 8 (16%) were found to be malignant. Increasing the size threshold for surgery to 6 cm reduced the number of ‘unnecessary’ operations without missing malignancy. These data support a more conservative approach towards adrenal incidentalomas in whom size >4 cm would be the sole indication for surgery.