18F-FDG-PET/CT Imaging of ACTH-Independent Macronodular Adrenocortical Hyperplasia (AIMAH) Demonstrating Increased 18F-FDG Uptake

摘要

Three nonrelated women (ages, 49, 51, and 60 yr) exhib-iting clinical features of hypercortisolism were diag-nosedwithACTH-independentCushing’ssyndrome.Endo-crine evaluations revealed an abnormal overnight 1-mgdexamethasonesuppressiontest(plasmacortisol,21.8,19.7,and 12.2 ? g/dl, respectively; normal, ?1.8 ? g/dl), elevated24-h urinary total cortisol (364, 811, and 410 ? g/24 h, re-spectively; normal, 30–300 ? g/24 h), and undetectableplasma ACTH. Unenhanced computed tomography re-vealed bilateral macronodular adrenal masses, with attenu-ation values up to 10, 25, and 23 Hounsfield units, respec-tively. Integrated 2-[fluorine 18] fluoro-2-deoxy-D glucose( 18 F-FDG) positron emission tomography/computed to-mography (PET/CT) revealed that18 F-FDG uptake in thesebilateral adrenal masses was visibly higher than that in theliver (Fig. 1). The maximum standardized uptake value(SUVmax), which is an index used to assess disease activityin FDG-PET imaging, was unexpectedly increased in theseadrenalmasses,reachinglevelsusuallyseeninmalignanttu-mors and metastases (SUVmax ?3.1) (1–4). The patientsunderwent bilateral adrenalectomy, and pathological find-ingsconfirmedtheclinicalhypothesisofACTH-independentmacronodular adrenocortical hyperplasia (AIMAH).