What is a testicular epidermoid inclusion cyst, and what are its cross-sectional imaging features?
A testicular epidermoid inclusion cyst is a benign lesion of germ cell origin, which consists of desquamated keratinized epithelium and keratin debris (ectodermal elements) surrounded by a fibrous wall. Treatment is with enucleation (rather than with radical orchiectomy for testicular cancer).
On cross-sectional imaging, it appears as a 1- to 3-cm focal well-circumscribed intratesticular lesion without blood flow or enhancement that has alternating low and high echogenicity/T2-weighted signal intensity rings with a characteristic lamellated “onion-skin” appearance. It can also have a “target” appearance with a hyperechoic or low T2-weighted signal intensity center and a hypoechoic or high T2-weighted signal intensity periphery
