Papillary Renal Cell Carcinoma in the Horseshoe Kidney

Sa Ying-Long, MD; Xu Yue-Min; Xie Hong; Xu Xiao-Lin

Disclosures

South Med J. 2010;103(12):1272-1274. 

In This Article

Discussion

The horseshoe kidney is probably the most common of all renal fusion anomalies. The anomaly consists of two distinct renal masses lying vertically on either side of the midline and connected at their respective lower poles by a parenchymatous or fibrous isthmus that crosses the midplane of the body. Nearly one third of all patients with a horseshoe kidney remain asymptomatic. When symptoms are present, they are related to hydronephrosis, infection, or calculus formation. The incidence of renal tumor in a horseshoe kidney is approximately 3 to 4 times greater than normal, and possibly the result of chronic obstruction, lithiasis, and infection.[2–4] The most common symptom that reflects these conditions is vague abdominal pain that may radiate to the lower lumbar region. The present case indicated that the right kidney connected the tumor, which oriented from the left renal lower pole by a parenchymatous isthmus (Fig.).

Papillary RCC remains one of the most common malignancies. Papillary RCCs characteristically show positive immunostaining for AMACR and CK78,30, but less frequently express CA-IX and/or CD10 (59% to 90% of cases).[5] Another factor is Xp11.2 translocation-caused RCC. These are typically composed of cells with abundant clear, to faintly eosinophilic, cytoplasm, arranged in nests and papillary structures. The tumor cells of Xp11 translocation carcinomas characteristically show positive nuclear immunostaining for TFE3, a finding that was not observed in any of the cases in our series.

In general, the isthmus lies anterior to the aorta and vena cava, and receives a branch from the main renal artery. The use of preoperative angiographic examination is necessary, especially in individual cases of strongly vascularized masses. Due to the low prevalence of focal nodular hyperplasia (FNH) cases requiring surgical procedure, a gathering of further information pertaining to these individual experiences is necessary to undertake some form of statistical analysis. In fact, selective angiographic examination for the specific tumor blood supply is able to reduce the intraoperative vascular injury, so blood transfusions were not necessary postoperatively.[6]

The surgical approach is guided more by individual preference than by necessity. The transperitoneal approach through a subcostal incision allows early ligation of the renal artery and vein before tumor manipulation. This is an essential technical consideration in the management of renal carcinoma. The division of the isthmus is essential in resecting renal cell cancer from a horseshoe kidney, not only to achieve complete access to the lymph nodes but also to normalize the course of the ureters. At present, when partial nephrectomy is not possible or not preferred, laparoscopy provides substantial convalescence benefits compared with conventional open surgery for patients undergoing radical nephrectomy. Laparoscopy is frequently used to treat early-stage kidney cancer,[7] due to the fact that postoperative recovery after laparoscopic donor nephrectomy is easier and faster than conventional open kidney donation. There are also no disadvantageous effects on cancer control or procedure-related complications. Survival from these tumors is related to the pathology and stage of the tumor at diagnosis, and not the renal anomaly.[8]

Papillary renal cell carcinoma in the horseshoe kidney is not common. Diagnosis of the disease is not difficult; however, saving the maximum residual renal function can be challenging. In our view, accurate preoperative assessment of renal function is necessary. The choice of surgical incision and the surgery itself aids in retention of the functional organization in patients with renal function, and reduces the chance of urinary bladder catheterization. Renal cell carcinomas are the most common primary tumors. A wide range of tumors are capable of causing endobronchial metastases, including those involving the bladder, thyroid, ovary, nasopharynx, prostate, uterine cervix, and testicles. There is general agreement that endobronchial metastases represent an advanced stage of disease with a poor prognosis.[9] We reported the case without finding tumor infiltration microscopically over these areas. Some studies have shown that whether the tumor is from the distant metastasis is directly related to the prognosis.[10] The final pathology results in a decision for patients with the need for further radical surgery, and even further radiotherapy and chemotherapy. Preoperative imaging is crucial in planning the surgical approach in such a case. Magnetic resonance angiography (MRA), magnetic resonance venography (MRV), and CT angiography have been advocated for imaging arterial anatomy. We speculate that imaging for venous involvement may be less accurate in fused kidneys due to smaller caliber renal veins and variable venous anatomy. The surgeon should be prepared for unexpected vascular anatomy, despite impressions gained from preoperative imaging.

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