Thrombus-like Tumor of Renal Cell Carcinoma Mimicking Transitional Cell Carcinoma of Kidney: A Case Report

[Clinical and pathological features of renal cell carcinoma with urinary tract tumor thrombus: 6 cases report and literature review]

OBJECTIVE

To investigate the clinical characteristics, diagnosis and treatment of renal cell carcinoma with urinary tract tumor thrombus.

METHODS

From January 1, 2015 to December 31, 2019, patients with renal cell carcinoma complicated with urinary tract tumor thrombus who were hospitalized in the Peking University Third Hospital and Beijing Friendship Hospital, Capital Medical University were retrospectively analyzed. Meanwhile, we reviewed the literature, and the reported patients of renal cell carcinoma with urinary tract tumor thrombus were also included in our study. The basic information, clinical manifestations, treatment, pathological characteristics and follow-ups of all the patients were analyzed.

RESULTS

In our study, 6 patients from the two hospitals and 16 patients from previous literature reports were included. There were 13 males and 9 females with an average age of 54.7 years (22-79 years). Fifteen patients had renal cell carcinoma on the left side, 6 on the right side, and 1 on the unknown side. Gross hematuria was the most common chief complaint, including 18 patients. One patient complained of weight loss, 1 patient complained of microscopic hematuria, and 1 patient was found by ultrasound examination. Tumor thrombus was classified as grade Ⅰ in 9 cases (the tumor embolus protruded into the renal pelvis, but did not reach the ureteropelvic junction), grade Ⅱ in 10 cases (the tumor embolus protruded into the ureter, but not into the bladder), and grade Ⅲ in 3 cases (the tumor embolus passed through the ureter and protruded into the bladder). Only 11 patients were diagnosed with renal cell carcinoma before operation. Radical nephrectomy was performed in 9 cases and nephroureterectomy in 12 cases. In pathological diagnosis, there were 15 cases of clear cell renal cell carcinoma, 1 case of papillary renal cell carcinoma, 1 case of chromophobe cell carcinoma, 1 case of mixed cell renal cell carcinoma, 4 cases of renal cell carcinoma with undetermined classification. Eleven patients were followed up for 3-31 months, and 3 patients had lung metastasis within 6 months.

CONCLUSION

Renal cell carcinoma with urinary tract tumor thrombus is rare in clinic. It needs to be differentiated from renal pelvis carcinoma in diagnosis. The treatment principle can refer to general renal carcinoma. For locally advanced cases, complete resection is the best treatment, and its oncological prognosis needs more long-term and large-scale follow-up observation.

Urinary collecting system invasion on multiphasic CT in renal cell carcinomas: prevalence, characteristics, and clinical significance

PURPOSE

The aim of this study was to determine the prevalence of collecting system invasion (CSI) on multiphasic CT, validate the pathological findings, and investigate the relationship between CSI and clinical outcomes in patients with renal cell carcinomas (RCC).

METHODS

Patients pathologically diagnosed with RCC between January 2008 and December 2017 were retrospectively enrolled in this study. They were divided into two groups according to the presence of CSI on multiphasic CT images. Patients' clinical characteristics, radiological findings, and overall survival (OS) and recurrence-free survival (RFS) rates were analyzed and compared between the groups. In addition, the correlation of radiological findings with pathological findings was investigated.

RESULTS

Among the included 347 kidneys of 340 patients, CSI was observed in 11 kidneys (3%; 95% confidence interval, 1.3-5.0%). In all the 11 kidneys, the tumors were pathologically diagnosed as clear cell RCC, and in one kidney, the tumor also had sarcomatoid features. When pathological CSI served as the standard of reference, the sensitivity, specificity, and accuracy of CSI on CT were 50%, 99.7%, and 97.1%, respectively. The OS and RFS rates were not significantly different between patients with CSI on CT and those without CSI.

CONCLUSION

This study found that the prevalence of RCC-related CSI was 3%. Because of the low prevalence, we cannot exclude the possibility that CSI on CT would be associated with the OS and RFS. Further studies are needed to determine whether CSI on CT can be an independent prognostic factor for survival in patients with RCC.

A Case of Type 1 Papillary Renal Cell Cancer with Pelvic Tumor Thrombus Masquerading as Urothelial Cancer with Review of Literature

Background: Adult renal tumors vary from renal cell carcinoma (RCC) to upper tract urothelial cancer (UTUC). Tumor characteristics such as renal vein and inferior vena cava tumor thrombus are usually seen with RCC, but tumor thrombus into pelvicaliceal system (PCS) is a rare entity in RCC. At present only 11 cases have been reported in the literature. Case Presentation: We report an unusual case of papillary type 1 RCC in a young Muslim man mimicking as UTUC radiologically and found to have free tumor thrombus in PCS. At follow-up of 6 months after right nephroureterectomy with bladder cuff excision, he is doing well clinically and radiologically without any recurrence. Conclusion: RCC with tumor thrombus into PCS is an uncommon entity. It can give similar appearance as an urothelial cancer of the pelvis on radiologic imaging. Pelvic tumor thrombus is now considered as a factor of poor prognostic importance and rarely encountered with pure papillary type of RCC.

Clear Cell Renal Cell Carcinoma with a Ureteral Thrombus

Introduction: Cancers of the kidney, arising from either the renal parenchymal tissue or the renal pelvis, is among the 13 commonest types of malignancy globally, accounting for between 3% and 4% of all newly diagnosed cancers. Renal cell carcinoma (RCC) accounts for 85% of all malignant renal neoplasms. We present a rare case of an RCC directly extending into the renal pelvicalyceal system and with a thrombus within the ureter.

Case Presentation: A 39-year-old woman presented with a long-standing history of worsening left flank pain, intermittent visible hematuria, and a fullness in the left flank. Apart from an ill-defined left flank mass with pain on palpation, there was nothing remarkable on clinical examination. Contrast-enhanced abdominal CT scan images showed a large, heterogeneously enhancing soft tissue mass arising from the lower pole of the left kidney. The collecting system and the left proximal ureter were poorly visualized. A tentative diagnosis of RCC, cT_3aN₀M₀ was made. Intraoperatively, we identified a large, left lower pole renal mass, displacing the pedicle superiorly. In addition, we found a bulky, dilated proximal ureter. A decision was made intraoperatively to proceed with radical nephrectomy and ureterectomy.

Conclusion: We report a rare case of RCC directly invading from the renal pelvis and down the ureter as a thrombus mass, with no microscopic individual tumor implants in the ureter wall, invasion of the renal vein, or invasion of adjacent organs. To our knowledge, only four such cases have been reported in English literature, and as a result, very few theories explaining renal pelvic invasion and direct growth down the ureter have been postulated. This highlights the significance of adding invasion of the pelvicalyceal system as part of the most recent, updated tumor node metastases classification. In future, consideration needs to be given to include the extension of RCC into the ureter and/or bladder.