Multiple penile schwannomas and their magnetic resonance imaging characteristics.

Penile schwannoma is a rare encapsulated nerve sheath tumor of the peripheral nerve in the penis. Here, we report a case of multiple, painful, beadlike, nodular tumors in the penis of a 40-year-old man. The nodules showed well-defined margins and hypoechoic areas on gray-scale ultrasonograms. They showed high signal intensity on fat-saturated T2-weighted magnetic resonance imaging (MRI) and intense enhancement on gadolinium-enhanced T1-weighted MRI, compatible with their myxoid content. The nodules pressed against the tunica albuginea and some caused inward indentation, which we considered as indirect evidence of the tumor location. In conclusion, the MRI characteristics and location of the nodules together enable presurgical diagnosis of penile schwannomas, which is especially useful in asymptomatic patients and those unwilling to undergo surgery.