Rare benign adrenal lesions

While most benign lesions of the adrenal glands represent either an adrenocortical adenoma or a myelolipoma, the advent and frequent use of high-resolution radiological investigations have led to relatively increased incidental discovery of rare adrenal lesions, specifically benign adrenal cysts, adrenal ganglioneuromas, adrenal schwannomas, adrenal hemorrhage, and adrenal calcifications. Radiological characteristics of the different rare benign adrenal lesions could vary from distinct to indeterminate. Though typically nonfunctional, these rare lesions require evaluation for adrenal hormone excess, as they may phenotypically appear similar to pheochromocytoma or adrenocortical carcinoma and could sometimes be associated with or conceal an underlying functional adrenal tumor. In this review, we discuss the various rare benign adrenal lesions, emphasizing a practical perspective.