Approach to Fine Needle Aspiration of Adrenal Gland Lesions

Adrenal gland lesions are present in 1% to 5% of patients and are most commonly identified incidentally on abdominal imaging. Fine needle aspiration (FNA) cytology plays an important role in the initial workup of adrenal gland nodules, especially in patients with a known history of malignancy. The most common reason for adrenal gland FNA is to differentiate benign adrenal lesions, such as adrenal cortical adenoma, from metastatic malignancy. However, there is a significant cytomorphologic overlap between primary and metastatic adrenal neoplasms. This review focuses on the current state of adrenal gland FNA cytology, with an emphasis on distinguishing adrenocortical adenoma from carcinoma and adrenal cortical neoplasms from metastatic malignancies. The role of immunohistochemistry in specifically diagnosing adrenal neoplasms is discussed. Proposed diagnostic classification systems for adrenal gland FNA cytology are also described.