Open partial nephrectomy for a collision renal cell carcinoma in a transplant kidney: A case report

Case report: A collision tumor of clear cell renal cell carcinoma and clear cell papillary renal cell tumor

We report the case of a 51-year-old woman who was initially hospitalized in the respiratory department with cough and fever. Urinary computed tomography (CT) showed two different incidental masses in the right kidney. The patient underwent a radical right nephrectomy without lymph node dissection and postoperative adjuvant treatment. The pathological examination of the surgical specimens showed a collision tumor composed of a clear cell renal cell carcinoma (CCRCC) and a clear cell papillary renal cell tumor (CCPRCT). To the best of our knowledge, this is the first such case reported to date. No recurrence of local or distant metastasis was found during routine follow-up 14 months after the operation.

Management of renal cell carcinoma in transplant kidney: a systematic review and meta-analysis

INTRODUCTION

After transplantation, approximately 10% of renal cell carcinomas are detected in graft kidneys. These tumors (gRCC) present surgeons with the difficulty of finding a treatment that guarantees both oncological clearance and maintenance of function. We conducted a systematic review and an individual patient data meta-analysis on the oncology, safety and functional outcomes of the available treatments for gRCC.

EVIDENCE ACQUISITION

A systematic search was performed across MEDLINE, EMBASE, and Web of Science including any study reporting perioperative, functional and survival outcomes for patients undergoing graft nephrectomy (GN), partial nephrectomy (PN) or thermal ablation (TA) for gRCC. Quade's ANCOVA, Spearman Rho and Pearson χ², Kaplan-Meier, Log-rank and Standard Cox regression and other tests were used to compare treatments. Studies' quality was evaluated using a modified version of Newcastle Ottawa Scale.

EVIDENCE SYNTHESIS

A number of 29 studies (357 patients) were included. No differences between TA and PN were found in terms of safety, functional and oncological outcomes for T1a gRCCs. When applied to pT1b gRCC, PN showed no difference in complications, progression or cancer-specific deaths compared to smaller lesions; PN validity for pT2 gRCCs should be considered unverified due to lack of sufficient evidence. The efficacy and safety of PN or TA for multiple gRCC remain controversial. In case of non-functioning, large (T≥2), complicated or metastatic gRCCs, GN appears to be the most reasonable choice. Quality of evidence ranged from very low to moderate. Studies with large cohorts and longer follow-up are still needed to clarify oncological and functional differences.

CONCLUSIONS

PN and TA might be offered as a nephron-sparing treatment in patients with T1a gRCC. There is no significant difference between these options and GN in terms of oncological outcomes and complications. PN and TA offer similar functional outcomes and graft preservation. PN for T1b gRCC seems feasible and safe, but its validity should be considered unverified.

Renal collision tumours: three additional case reports

Background

Multiple kidney tumours are frequently seen in hereditary syndromes and familial diseases. Renal collision tumours (RCT) are characterized by the simultaneous existence of different and unrelated tumour types within the same location in the kidney, forming a single, heterogenous lesion. RCT are uncommon histological entities with distinctive features. The most frequent subtypes include clear cell renal cell carcinoma (CCRCC), papillary renal cell carcinoma (PRCC), chromophobe renal cell carcinoma (CRCC), and collecting duct carcinoma (CDC).

Case presentation

Here, we report three sporadic cases of RCT successfully treated by nephrectomy and confirmed by histological analysis. The first case was of a 64-year-old man diagnosed with RCT composed of a stage 2 nucleolar grade 3 CCRCC and a stage 1a nucleolar grade 2 type 1 PRCC. The second case was of a 68-year-old woman diagnosed with a combined nucleolar grade 2 type 1 PRCC and an angiomyolipoma (non-assessed stage), while the third case was of a 59-year-old woman diagnosed with a combined stage 1a nucleolar grade 3 CCRCC and a stage 1b CDC.

Conclusions

Due to the rarity of RCT, there are no standard guidelines for their management. Hence, the prognosis is considered to be associated with the most aggressive component, possibly the tumour with the highest nucleolar grade and stage. The histogenesis of RCT remains debated, and increase in knowledge regarding this can help enable the development of targeted therapies for advanced or metastatic tumours.