Multicystic dysplasia in one-half of a horseshoe kidney with megaureter and lower ureteric atresia.

During evaluation of chronic abdominal pain, a 9-year-old male was found to have a horseshoe kidney (HSK) with multicystic dysplasia (MCD) of the left-sided component. Attached to the MCD was a very large, tortuous ureter occupying almost the whole left side of the abdomen. This ureter on dissection was found to end blindly adjacent to the bladder. MCD of one-half of a HSK is an unusual lesion. Its association with a large megaureter with juxtavesical atresia is a unique event. In HSKs, controversy exists about the need to remove a small dysplastic segment. If this segment is associated with a large ureter, as in our case, removal is mandatory in order to avoid pain and infection.