Tumour size in adrenal tumours: its importance in the indication of adrenalectomy and in surgical outcomes-a single-centre experience.

Objective: To evaluate the relevance of tumour size in adrenal tumours in the estimation of malignancy risk and in the outcomes of adrenalectomy.

Methods: We evaluate the histological results and surgical outcomes (intraoperative and postsurgical complications) in a retrospective single-centre cohort of patients without history of active extraadrenal malignancy with adrenal tumours consecutively operated in our centre during January 2010 and December 2020. We compared these results in lesions smaller and larger than 40, 50, and 60 mm.

Results: Of 131 patients with adrenal tumours who underwent adrenalectomy, 76 (58.0%) had adrenal masses measuring ≥ 40 mm; 47 were > 50 mm and 28 > 60 mm. The final diagnosis was adrenocortical carcinoma (ACC) in 7 patients, pheochromocytoma in 35, and benign lesions in the remaining. All patients with ACC had adrenal masses > 50 mm, with Hounsfield units > 40 and low lipidic content in the CT. The risk of ACC and pheochromocytoma increased as tumour size did. The diagnostic accuracy of tumour size was quite good for the prediction of ACC (AUC-ROC 0.883). Nevertheless, when only adrenal tumours with HU < 40 were considered, the risk of ACC was 0% independent of tumour size. For pheochromocytomas, the risk was of 8.6% independent of tumour size for lesions with < 20HU. The risk of intraoperative and postoperative complications was independent of tumour size.

Conclusion: Risk of malignancy and of pheochromocytoma increased as tumour size increased, but, in the presurgical estimation of malignancy risk and of pheochromocytoma, not only tumour size, also lipidic content and other radiological features, should be considered. The risk of complications was independent of tumour size, but hospital stay was longer in patients with complication or open approach.