Figure 3b. Adrenal adenoma in a 63-year-old woman with a history of mucosa-associated lymphoid tissue lymphoma. Previous CT images had shown a 1.4-cm left adrenal nodule. Axial (a–c) and coronal (d–f) CT (a, d), PET (b, e), and fused PET-CT (c, f) images show an area with minimally increased FDG uptake (arrow) relative to the liver, a finding that corresponds to a left adrenal mass. The unenhanced CT attenuation value of the mass (0 HU) was consistent with an adenoma. The patient remains disease free in other anatomic locations. A minimal degree of FDG uptake can be seen in adenomas, whose incidental detection is a relatively common occurrence. In patients with a history of known malignancy and equivocal CT findings (especially with lipid-poor adenomas), fusion PET-CT is valuable in differentiating adenomas from other neoplasms given the usual lack of significant FDG avidity in adenomas.