[Use of 18F-FDG-positron emission tomography in presurgical evaluation of nonspecific or suspectious adrenal masses in non-oncologic patients].

BACKGROUND AND OBJECTIVE: Our purpose was to assess the utility of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in pre-surgical characterization of adrenal masses. These masses were incidentally discovered in non-oncologic patients or during the study of endocrine hormone overproduction. These nodular lesions showed nonspecific or suspicious radiological features in the imaging tests routinely performed (CT and/or MRI).

PATIENTS AND METHODS: This is a cross-sectional and prospective study in 12 patients with adrenal masses which were radiologically non-specific or suspicious for malignancy before adrenalectomy. An 18F-FDG-PET was made and quantitative FDG uptake (SUVmax) in the adrenal region (adrenal SUVmax) and liver (liver SUVmax), and the ratio SUVmax adrenal/liver was calculated. These parameters were related to the pathological findings. We evaluated the accuracy of the test by receive operating curves (ROC).

RESULTS: The ROC to discriminate between benign and malignant lesions showed that the SUVmax was a better parameter than size or SUVmax adrenal/liver ratio. Using a SUVmax cutoff value≥3.1, sensitivity, specificity, positive and negative predictive value of the test were 100, 67, 50 and 100%, while a SUVmax adrenal/liver ratio≥1.8 showed a sensitivity, specificity, positive and negative predictive value of 67, 100, 100 and 90%, respectively. The presence of a SUVmax adrenal/liver ratio≥1.8 showed a statistically significant association with carcinoma occurrence.

CONCLUSION: 18F-FDG-PET may be useful in the characterization of nonspecific or suspicious adrenal masses discovered in patients without a previous history of cancer. Its use in some cases could avoid unnecessary interventions.