May an adrenal incidentaloma change its nature?

Background: Up to 70% of adrenal masses detected in patients affected by extra-adrenal malignancy are metastatic lesions. Therefore, detection of an adrenal mass in patients with active or previous malignancy requires a careful differential diagnostic workup. 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) is increasingly being used to determine the malignant potential of adrenal lesions. Clinical case: We report the case of a 64-year-old man who had a single adrenal metastasis due to non-small-cell lung carcinoma developing on a pre-existing benign adrenal lesion. This metastasis occurred in a phase of perceived oncological remission and was detected thanks to 18F-FDG-PET/CT showing a focal adrenal uptake. Contrast-enhanced computed tomography (CT), performed as part of oncological follow-up, and MRI with chemical shift sequences did not lead to the correct diagnosis. The patient underwent laparoscopic adrenalectomy and the pathological evaluation confirmed a lung carcinoma metastasis. Conclusion: The present case highlights the peculiarity of the follow-up of adrenal masses in cancer patients and the primary role of 18F-FDG-PET/CT in the management of such patients.