Congenital urachal anomalies
Congenital urachal anomalies are a spectrum of potential anomalies that can occur due to incomplete involution of the urachus.
A urachal remnant occurs in approximately 1 in 5000 patients.
By birth, the urachus is obliterated and becomes a vestigial structure known as the median umbilical ligament (not to be confused with the medial umbilical ligament, which is a separate structure that lies laterally to the median umbilical ligament).
In the absence of complete obliteration, the urachus persists in a number of configurations depending on the location and degree of obliteration.
There are four types of congenital urachal remnant anomalies. They are:
- communication between the bladder and umbilicus through a urachus that has not involuted
- commonest (~50%)
- a fluid-filled dilatation of the mid urachus
- next commonest (~30%)
- blind focal dilatation of the umbilical end of the urachus
- blind focal dilatation of the bladder end of the urachus
Treatment and prognosis
Congenital urachal remnants predispose to infection from urinary stasis and over a long period the remnant may develop malignancy (e.g. adenocarcinoma).
Treatment is not standardised. Some recommend surgical excision of the urachus if a remnant anomaly is present.
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