Surgical Treatment of Tumors Involving Kidneys With Fusion Anomalies: A Contemporary Series

Objective To report a contemporary series of surgically treated patients with tumors involving kidneys with fusion anomalies. Materials and Methods We retrospectively reviewed the medical records of all 10 patients treated at a single tertiary care institution for tumors involving kidneys with fusion anomalies between the years 2000 and 2015. One patient, diagnosed with lymphoma, did not undergo surgical treatment and was therefore excluded. Data regarding patient, tumor, and treatment characteristics were collected and described. Results The study cohort included 7 male and 2 female patients, at a median age of 52 years. Seven patients underwent open partial nephrectomy. Nephroureterectomy was performed on 2 patients; 1 open and 1 laparoscopic. All patients had localized disease at diagnosis. Tumor histologies were renal cell carcinoma in 5 patients, renal oncocytoma in 1 patient, urothelial carcinoma in 2 patients, and a well-differentiated liposarcoma involving the kidney in 1 patient. Accessory blood vessels were identified in 8 of 9 patients. Median estimated blood loss was 300 mL (interquartile range: 150-1000). Four patients had postoperative complications, including 3 major (Clavien grade ≥ 3) and 3 minor (Clavien grade ≤ 2) complications. During a median follow-up of 19.2 months (interquartile range: 3-34.8), 1 patient with urothelial carcinoma developed a bladder recurrence. None of the patients developed new-onset chronic kidney disease during the early postoperative period. Conclusion Localized renal cortical tumors in kidneys with fusion anomalies may be treated with partial nephrectomy; however, complication rates are relatively high. Preoperative imaging of the blood vessels is necessary, as most patients have an accessory blood supply.