In this radiology lecture, we discuss the ultrasound appearance of testicular epidermoid cyst. Key points include: * Testicular epidermoid cyst is a rare, benign, intratesticular neoplasm. * Most common in 2nd-4th decades, typically presents as a painless mass. * Lamellated, onion-like, bull’s-eye appearance: Alternating hyperechoic and hypoechoic concentric rings. * Appearance secondary to cyst filled with layers of keratin and lined with keratinizing squamous epithelium. * Non-vascular and sharply marginated. * Nonenhancing on MRI. * Important to recognize preoperatively because may be treated with conservative surgery. * Management somewhat controversial as originally diagnosed with orchiectomy. * Increasingly treated with enucleation if frozen sections of mass are consistent and tumor markers are negative.