Surgical Planning for Carcinoma in Horseshoe Kidneys Treated with Retroperitoneoscopic Partial Nephrectomy

Background: Horseshoe kidney (HSK) is a common congenital disease. Its incidence ranges from 1 in 400 to 1 in 1000, and it is often associated with chromosomal aneuploidies. Surgical approaches for tumor arising from HSKs are challenging because of the complicated vessel anatomy, poor mobility, and mass location. We report two patients diagnosed with tumors in HSKs who underwent retroperitoneoscopic partial- or heminephrectomy. Case Presentations: Case 1: A 55-year-old woman presented to the hospital complaining of recurrent back pain. A 3.0-cm tumor mass in a HSK and polycystic kidney was revealed on CT. Three-dimensional (3D) imaging revealed a parenchymal fusion in the superior pole of the left moiety of the HSK, supplied by two main arteries from the aorta. The patient underwent retroperitoneoscopic partial nephrectomy using the four-trocar technique. Case 2: A 50-year-old man was referred to the hospital for further examination of a left renal tumor in his HSK discovered on CT. 3D imaging revealed a 3.4-cm mass arising from the left moiety of a HSK with invasion of the left renal sinus. There were five arteries feeding the tumor. The patient underwent retroperitoneoscopic heminephrectomy after embolization of the main artery supplying the tumor, guided by digital subtraction angiography with the four-trocar technique. Conclusion: Retroperitoneoscopic surgical approaches are feasible for resection of tumors from HSKs. The option of retroperitoneoscopic partial- or heminephrectomy depends on the location and blood supply of the tumor.