Appearance of adrenal myelolipomas on 2-deoxy-2-(¹⁸F) fluoro-D-glucose positron emission tomography-computed tomography

With the widespread use of 2-deoxy-2-(¹⁸F) fluoro-D-glucose positron emission tomography-computed tomography (FDG PET/CT) in oncologic imaging, it has become increasingly important for physicians who interpret FDG PET/CT scans to confidently recognize the spectrum of incidentally encountered benign and malignant findings. The adrenal glands represent an interesting nexus of multiple rare and common benign intrinsic tumors as well as metastases from a variety of primary malignancies. Given the breadth of adrenal gland pathology, careful description of the FDG PET/CT appearance of these pathologies is of value to help reduce misinterpretation. In this manuscript, we retrospectively and systematically review the FDG PET/CT imaging characteristics of benign adrenal myelolipomas in a small consecutive patient series. The myelolipomas in this series demonstrated differing degrees of macroscopic fat visible on CT, with generally mild FDG uptake fusing to the non-fatty portions of the lesions. At imaging follow-up, all of the myelolipomas in this series remained unchanged in appearance, helping to confirm their benign nature. The typical appearance of a myelolipoma on FDG PET/CT is a fat-containing adrenal mass with low-level FDG uptake in the non-fatty aspects of the mass, and such a lesion requires no further imaging workup. (author)