[Ectopic ureter in the seminal vesicle. An unusual presentation]

An unusual case is presented of an ectopic ureter opening into a seminal vesicle associated with ipsilateral renal dysplasia in a 17-month-old boy. During the neonatal period, he had been diagnosed as having right renal agenesia. The patient presented with a rapidly growing tumor, a rare presenting symptom that led to misdiagnosis.