Transitional cell carcinoma (TCC) of the renal pelvis is an uncommon lesion, accounting for approximately 5% of all urinary tract tumors.1 Renal vein (RV) and/or inferior vena cava (IVC) tumor thrombus usually develops in renal cell carcinoma (RCC), and is a rare feature of renal TCC. The management and outcome of RCC and renal TCC are completely different. Occasionally, it can be difficult to distinguish between these two conditions preoperatively. We present a case of renal TCC with tumor thrombus in the RV extending to the IVC, for which the preoperative diagnosis on radiologic evidence was RCC with RV thrombus extending to the IVC.
A 55-year-old hypertensive woman had right flank pain for 2 years. She had a 30 pack-year history of smoking. She had no hematuria or weight loss. Results of her physical examination were unremarkable. Results of routine blood tests and urinalysis were within normal limits. Ultrasonography revealed a large heteroechoic mass involving the right kidney. On contrast-enhanced computed tomography (CT) scan, an 8.7 × 7.3 × 7.6-cm heterogeneously enhancing lesion with a few areas of necrosis, perinephric fat stranding, and involvement of the Gerota fascia was seen in the lower and interpolar region of the right kidney (Figure 1).
Multiple right renal hilar lymph nodes were present; the largest was 2 cm in size. A hypodense, nonenhancing filling defect was seen in the right RV extending to the junction of the right RV and IVC (Figure 2).
A radiologic diagnosis of RCC with RV and IVC thrombus (cT4N1M0) was made, and the patient underwent radical nephrectomy via a chevron incision. The RV contained a thrombus extending to its ostium. After ligation of the right renal artery, the thrombus retracted into the RV. A Satinsky clamp was placed distal to the RV ostium. The RV was ligated just beyond the thrombus. Hilar lymphadenectomy and ipsilateral adrenalectomy were also performed. Her postoperative period was uneventful.
Histopathologic investigation revealed a high-grade urothelial carcinoma with involvement of the renal parenchyma, sinus, proximal ureter, and adrenal gland. The RV thrombus and lymph nodes were involved by the tumor. Perinephric fat was free of tumor and the ureteric margin had carcinoma in situ.
On reviewing the imaging, CT revealed the mass to be more central than exophytic, without distortion of the reniform shape of the kidney. It also had a few dilated calyces, which may have suggested a tumor of urothelial origin rather than RCC. Adjuvant chemotherapy with cisplatin and gemcitabine was recommended.
Thrombosis of the RV and IVC has been reported in 21% to 35% and 4% to 10% of cases of RCC, respectively.2 However, renal TCC with RV/IVC thrombus is an uncommon, late finding.3-5 The incidence of IVC involvement in RCC has been estimated to be 48-fold higher than in renal TCC.4 Huber and colleagues4 reviewed their series of 102 cases of renal TCC managed over 20 years and found an incidence of 5%. However, fewer than 40 cases have been reported to date.5 Approximately 90% of cases have been reported involving the right kidney,6 and most cases are high-grade tumors.7 Moreover, renal TCC more commonly presents with a higher stage than TCC of the urinary bladder because of the thin muscle layer of the renal pelvis.8
Large, infiltrating TCC may be difficult to differentiate from other common and uncommon masses such as RCC with RV thrombus, xanthogranulomatous pyelonephritis, lymphoma, or metastases.3 However, the renal mass in our patient appeared to have more of an infiltrative radiologic pattern, with a preserved reniform shape of the kidney, which is not typical of RCC. The first differential diagnosis given by the radiologist was RCC in view of the RV and IVC thrombus. An infiltrative pattern of growth that preserves the reniform renal shape is more suggestive of urothelial carcinoma or lymphoma.9 Percutaneous needle biopsy may be indicated in such cases.10
With RV/IVC thrombus, preoperative differentiation between upper tract TCC and RCC is important for both management and prognostication; renal TCC with RV/IVC tumor thrombus has a poorer prognosis than RCC with venous thrombus.7,11
In renal TCC, those with venous involvement have poor prognosis, with an estimated median survival of 8.9 months,4 as compared with 12.9 months for patients with locally advanced renal TCC without venous involvement.12 The tumor is usually locally advanced in such cases. More than 50% of patients die within the first year of diagnosis.5,13
Most reported cases were treated surgically. When there is a strong suspicion of renal TCC on preoperative imaging, examination of an intraoperative frozen section helps in the choice of surgical procedure.14 If the frozen section reveals TCC, nephroureterectomy with thrombectomy and bladder cuff excision must be performed. The role of liver transplantation techniques in the surgical management of renal TCC with IVC thrombus has been described.15 Recently, IVC resection has been reported in one case of renal TCC with IVC invasion.16 Although radical surgery with IVC thrombectomy prolongs survival in patients with RCC,17 the exact role of radical extirpative surgery in the management of renal TCC with venous thrombus is not defined due to the limited available literature, as well as its aggressive nature and advanced presentation.
In our patient, the absence of hematuria and presence of the venous thrombus were the two key misleading points that clouded our vision toward correct preoperative diagnosis. Thus, renal pelvic TCC should be included in the differential diagnosis of an infiltrative renal mass with venous involvement and maintained reniform shape. Percutaneous needle biopsy in such doubtful cases may be considered.
