Prepubertal-type teratomas are rare, especially in postpubertal patients. We present a case of a 43-year-old man with a palpable painless mass in the left-sided testis discovered by accident. Scrotal ultrasound and magnetic resonance imaging revealed a 2.7×2.0 cm mass inside the left testis, and malignancy could not be excluded, though classical serum tumor makers were within normal limits. Radical testicular resection was then conducted, and the pathologic report proved the mass to be a testicular epidermoid cyst, a rare form of prepubertal-type teratoma. Relevant published literature is also reviewed in our text.