Neoplasia in horseshoe kidney with pyelic fusion and crossed single ureter.

Horseshoe kidney with pyelic fusion and crossed single ureter is a rare anomaly, with only 3 cases described in the literature. Such anomaly can be accompanied by other abnormalities, such as congenital scoliosis and situs inversus totalis. We present one case of this malformation associated with malignant neoplasia, treated with partial nephrectomy.