What is a testicular adrenal rest, and what are its cross sectional imaging features?
An adrenal rest is a rare benign lesion that is composed of hyperplastic ectopic adrenal gland tissue. It is typically seen in patients with a history of congenital adrenal hyperplasia secondary to elevation of adrenocorticotropic hormone (ACTH) levels. Appropriate corticosteroid replacement therapy can lead to regression of adrenal rests.
On cross-sectional imaging, multiple bilateral oblong-shaped lesions are seen in the testicles, usually in the region of the mediastinum testis. On US, these are usually hypoechoic or sometimes hyperechoic relative to testicular parenchyma, and they have spoke-like vascularity on Doppler US. On MRI, these have intermediate/slightly high T1-weighted and low T2-weighted signal intensity relative to testicular parenchyma, along with mild enhancement.