Epidermoid Cyst of the Testis: Sonographic Characteristic Appearance

Intratesticular epidermoid cysts are rare, benign, well-defined, and solitary keratinized intratesticular lesions. They usually present as a painless, discrete, and firm swollen area before being diagnosed. Preoperative diagnosis of epidermoid cysts is often difficult. Sonography is a useful imaging modality in the preoperative assessment of testicular lesions. Although it is difficult to distinguish epidermoid cysts from germ cell tumors, certain sonographic characteristics such as the classical "onion-peel" appearance, the negative tumor markers, and the underlying symptoms should raise the suspicion of epidermoid cysts.