[A case of patent urachus in an adult male].

A 31-year-old man was referred to our hospital for evaluation of urachal rest. The history of his present illness dated back to birth, when the umbilicus was projected and urinary discharge was noted. At that time, the symptom of discharge had spontaneously subsided. At the age of 22, however, the patient again experienced discharge from the umbilicus. Although he did not seek treatment, after six years this symptom disappeared. Around this time, however, pyuria was revealed during medical examination, and abdominal ultrasonography (US) suggested the presence of urachal rest. At the time of hospitalization, physical examination revealed that the patient's right testis was not palpable. He was diagnosed with patent urachus with hemilateral aplasia and monorchism by US, computed tomography, magnetic resonance imaging and cystoscopy. The patient subsequently underwent radical operation. Patent urachus in adults is very rare, and only a few cases have been reported. To our knowledge, only one previously reported case involved a recurrence after spontaneous healing. Further, this is the first report of a patient with patent urachus with hemilateral aplasia and monorchism. Radical operation is generally recommended, based on the fact that very few cases heal conservatively.