FDG-PET/CT is a modality that can further characterize whether a mass is benign versus malignant, as malignant lesions have increased metabolic activity and, therefore, increased glucose avidity compared with benign lesions. Both qualitative and quantitative assessment using standard uptake values (SUVs) is performed to evaluate a lesion. Malignant lesions show increased activity compared with benign lesions with a sensitivity between 93% and 100% [22]. If pheochromocytoma is suspected, then FDG, DOPA, DOTATATE, or MIBG studies can be utilized to improve detection when anatomic localization is inconclusive, to identify additional lesions in the setting of hereditary disease, or to evaluate for metastatic disease [23]. Discussion of Procedures by Variant Variant 1: Indeterminate adrenal mass, less than 1 cm on initial imaging. No diagnostic benign imaging features. No history of malignancy. For patients with no prior history of malignancy and an incidentally detected adrenal mass <1 cm without diagnostic benign imaging characteristics on initial study, the mass is most likely benign [12,24]. One study by Herrera et al [5] examined 342 patients without a history of malignancy and found that the rate of malignancy in adrenal nodules was only 1.5% and that all malignant lesions were >5 cm. Although many guidelines exist regarding the appropriate time interval for follow-up of adrenal nodules, no agreement has been achieved. Stability of a lesion should be assessed by repeat imaging for nodules >1 cm, but there is no literature supporting further evaluation of lesions <1 centimeter. CT Abdomen For lesions <1 cm and no history of malignancy, there is no primary evidence supporting the use of CT for initial evaluation. Metastatic disease to the adrenal gland without a known history of primary malignancy is unusual [4,5]. In a study of 1,049 incidental adrenal masses in patients with no known history of cancer, none were malignant.
Adrenal Mass Evaluation. FDG-PET/CT is a modality that can further characterize whether a mass is benign versus malignant, as malignant lesions have increased metabolic activity and, therefore, increased glucose avidity compared with benign lesions. Both qualitative and quantitative assessment using standard uptake values (SUVs) is performed to evaluate a lesion. Malignant lesions show increased activity compared with benign lesions with a sensitivity between 93% and 100% [22]. If pheochromocytoma is suspected, then FDG, DOPA, DOTATATE, or MIBG studies can be utilized to improve detection when anatomic localization is inconclusive, to identify additional lesions in the setting of hereditary disease, or to evaluate for metastatic disease [23]. Discussion of Procedures by Variant Variant 1: Indeterminate adrenal mass, less than 1 cm on initial imaging. No diagnostic benign imaging features. No history of malignancy. For patients with no prior history of malignancy and an incidentally detected adrenal mass <1 cm without diagnostic benign imaging characteristics on initial study, the mass is most likely benign [12,24]. One study by Herrera et al [5] examined 342 patients without a history of malignancy and found that the rate of malignancy in adrenal nodules was only 1.5% and that all malignant lesions were >5 cm. Although many guidelines exist regarding the appropriate time interval for follow-up of adrenal nodules, no agreement has been achieved. Stability of a lesion should be assessed by repeat imaging for nodules >1 cm, but there is no literature supporting further evaluation of lesions <1 centimeter. CT Abdomen For lesions <1 cm and no history of malignancy, there is no primary evidence supporting the use of CT for initial evaluation. Metastatic disease to the adrenal gland without a known history of primary malignancy is unusual [4,5]. In a study of 1,049 incidental adrenal masses in patients with no known history of cancer, none were malignant.