Indeterminate adrenal mass in patients with cancer: evaluation at PET with 2-[F-18]-fluoro-2-deoxy-D-glucose.

Abstract

To evaluate the ability of positron emission tomography (PET) to characterize adrenal masses in patients with cancer. Twenty-four adrenal masses (size range, 1.5-10.0 cm [mean, 2.8 cm]) in 20 patients (13 men and seven women) with cancer (lung [n = 10], colon [n = 3], lymphoma [n = 3], miscellaneous [n = 4]) were evaluated. PET was performed in fasting patients 45 minutes after infusion of 5-10 mCi (185-370 MBq) of 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG). PET images were correlated with findings at computed tomography (CT), surgery, and/or percutaneous biopsy. Fourteen adrenal masses were proved malignant at surgery (n = 4), biopsy (n = 7), or follow-up (n = 3). Ten lesions were proved benign at biopsy (n = 4) or follow-up CT (n = 6). PET helped correct differentiation of benign from malignant adrenal lesions in all patients. A statistically significant difference (P < .001) was seen between mean tumor-to-background ratios for malignant (mean, 7.4; range, 2.9-16.6; median, 6.9) versus benign (mean, 0.8; range, 0.2-1.2; median, 0.6) adrenal lesions. PET helped correct differentiation of benign from malignant adrenal lesions.