A Paratesticular Serous Borderline Tumor in a Pediatric Patient With Proteus Syndrome.

Proteus syndrome is a rare disorder of asymmetric overgrowth of various tissues of the body and is associated with specific tumors appearing before the second decade. Although there have been reports of lesions of the genitourinary tract associated with Proteus syndrome, a case of serous borderline tumor of the paratestis has not been previously recorded. We report the first such case in a 20-month-old child who presented with a left-sided testicular mass that was found on histology to be a serous borderline tumor of the paratestis. Surgical management included a left inguinal radical orchiectomy and surveillance follow-up.