All tumors were without diagnostically benign features on CT or MRI. In this small series, a tumor/liver SUVmax ratio >1.8 yielded 100% sensitivity and specificity for malignancy. 11C-metomidate has been found to localize in adrenocortical tumors and is useful for determining whether a tumor is of adrenocortical origin. However, it cannot distinguish between benign and malignant tumors [64,65]. PET/CT sensitivity to small lesions is diminished and may not detect lesions <1 cm. Image-Guided Biopsy Adrenal Gland In the setting of known primary malignancy, adrenal mass biopsy can be performed when noninvasive tests are inconclusive, when enlarging adrenal masses are seen at follow-up imaging, or to confirm the presence of an adrenal metastasis [81]. If other metastases are present, biopsy may not be necessary. Fine-needle aspiration alone cannot reliably be used to differentiate adrenocortical carcinoma from adrenal adenoma. Also, the sensitivity of needle biopsy for adrenocortical carcinoma is low. In one study, the sensitivity of needle biopsy for detecting adrenocortical carcinoma was reported as 50% [48]. Another study reported the sensitivity as 70% maximally [49]. In addition, percutaneous biopsy of adrenal lesions is not without risk. Complication rates range from 8% to 12% and consist of bleeding, pneumothorax, infection, and anecdotes of tumor seeding of needle tracts. Careful correlation with clinical and endocrinological data is needed, combined with knowledge of other features, such as tumor size and imaging characteristics, to distinguish adenoma from carcinoma due to the possibility of sampling error. Thus, biopsy is better suited to a population with a high risk of malignant lesions and is most useful when noninvasive imaging studies are negative or inconclusive. MRI Abdomen Qualitative and quantitative MRI methods have been used to attempt to distinguish between adenomas and nonadenomas.
Adrenal Mass Evaluation. All tumors were without diagnostically benign features on CT or MRI. In this small series, a tumor/liver SUVmax ratio >1.8 yielded 100% sensitivity and specificity for malignancy. 11C-metomidate has been found to localize in adrenocortical tumors and is useful for determining whether a tumor is of adrenocortical origin. However, it cannot distinguish between benign and malignant tumors [64,65]. PET/CT sensitivity to small lesions is diminished and may not detect lesions <1 cm. Image-Guided Biopsy Adrenal Gland In the setting of known primary malignancy, adrenal mass biopsy can be performed when noninvasive tests are inconclusive, when enlarging adrenal masses are seen at follow-up imaging, or to confirm the presence of an adrenal metastasis [81]. If other metastases are present, biopsy may not be necessary. Fine-needle aspiration alone cannot reliably be used to differentiate adrenocortical carcinoma from adrenal adenoma. Also, the sensitivity of needle biopsy for adrenocortical carcinoma is low. In one study, the sensitivity of needle biopsy for detecting adrenocortical carcinoma was reported as 50% [48]. Another study reported the sensitivity as 70% maximally [49]. In addition, percutaneous biopsy of adrenal lesions is not without risk. Complication rates range from 8% to 12% and consist of bleeding, pneumothorax, infection, and anecdotes of tumor seeding of needle tracts. Careful correlation with clinical and endocrinological data is needed, combined with knowledge of other features, such as tumor size and imaging characteristics, to distinguish adenoma from carcinoma due to the possibility of sampling error. Thus, biopsy is better suited to a population with a high risk of malignant lesions and is most useful when noninvasive imaging studies are negative or inconclusive. MRI Abdomen Qualitative and quantitative MRI methods have been used to attempt to distinguish between adenomas and nonadenomas.