A 28-year old man, with previous history of chronic abdominal pain, was referred to our nuclear medicine center for an F-FDG PET/CT following the fortuitous discovery of a 48-mm right adrenal gland lesion of heterogeneous density at the CT scan. The PET/CT showed an isolated heterogeneous significant uptake evocative of neoplasia. Surprisingly, the anatomopathological analysis after surgery revealed an adenoid tumor of the adrenal gland. This case of a rare benign tumor can be a source of false-positive and mimicking malignancies in the exploration of adrenal lesions.