Absent vas deferens in association with renal abnormalities.

Absence of the vas deferens, especially if unilateral, should alert the clinician to an underlying renal anomaly, and further urological investigation is mandatory. If the vas is shown to be bilaterally absent in an infant, cystic fibrosis should be excluded. In the context of vasectomy, exploration of the palpably absent side should be unnecessary if intravenous urography detects a combined anomaly, although post-operative seminal analysis will still need to be performed.