Renal Squamous Cell Carcinoma of a Native Kidney After Renal Transplant: A Case Report

How to manage renal masses in kidney transplant recipients? A collaborative review by the EAU-YAU kidney transplantation and renal cancer working groups

INTRODUCTION

Kidney transplant (KT) recipients have a four-times higher risk of renal malignancies compared to general population. As these patients frequently harbor bilateral or multifocal tumors, the management of renal masses is still under debate.

OBJECTIVE

To explore the current management of the native kidney masses in KT patients.

ACQUISITION OF EVIDENCE

We performed a literature search on MEDLINE/PubMed database. A number of 34 studies were included in the present review.

SYNTHESIS OF EVIDENCE

In frail patients with renal masses below 3 cm, active surveillance is a feasible alternative. Nephron-sparing surgery is not justified for masses in the native kidney. Radical nephrectomy is the standard treatment for post-transplant renal tumors of the native kidneys in KT recipients, with laparoscopic techniques leading to significantly less perioperative complication rates as compared to the open approach. Concurrent bilateral native nephrectomy at the time of transplantation can be considered in patients with renal mass and polycystic kidney disease, especially if no residual urinary output is present. Patients with localized disease and successful radical nephrectomy do not require immunosuppression adjustment. In metastatic cases, mTOR agents can ensure efficient antitumoral response, while maintaining proper immunosuppression in order to protect the graft.

CONCLUSIONS

Post-transplant renal cancer of the native kidneys is a frequent occurrence. Radical nephrectomy is most frequently performed for localized renal masses. A standardized and widely-approved screening strategy for malignancies of native renal units is yet to be implemented.

Primary Renal Squamous Cell Carcinoma in Native Polycystic Kidney and Ureter 16 Years After Living Donor Kidney Transplant

We describe a case of a 55-year-old woman with polycystic kidney disease who received a living donor kidney transplant 16 years earlier and was on immunosuppressive therapy with satisfactory renal function. The donor was her mother. The patient presented with flank pain on the right side and macrohematuria, and noncontrast computed tomography and magnetic resonance imaging led to the diagnosis of tumors in the remaining right native polycystic kidney and ureter, as well as secondary retroperitoneal dissemination. We performed right radical nephrectomy and ureterectomy with extirpation of 2 metastases; the left native kidney remained intact. Histology showed squamous metaplastic changes and invasive epithelial neoplasm in the lumen of the renal pelvis and ureter with extensive squamous differentiation positive for nuclear p63 as squamous cell immunohistochemical marker. After surgery, an immunosuppressive therapy with methylprednisolone was administered, without calcineurin inhibitors and mycophenolate mofetil. Twelve months later the patient was still alive, with a glomerular filtration rate of 29 mL/min. Needs remain for further treatment modalities in patients with primary squamous cell carcinoma in nonfunctioning kidneys and improvements in imaging technique accuracy.

A case report of complete pathological remission after chemotherapy in a patient with primary renal squamous cell carcinoma

This is the first case report of the outcomes of systemic chemotherapy in a patient with locally advanced renal squamous cell carcinoma, a rare tumor, as well as the first next generation sequencing study of this rare tumor. The patient's main symptoms were fever and low back pain. Initial positron emission tomography and computed tomography (PET-CT) suggested a malignant renal tumor at onset, but biopsy confirmed renal squamous cell carcinoma. Next generation sequencing showed a low level of microsatellite instability (MSI-L), a high tumor mutational burden (TMB-H), a high neoantigen burden (TNB-H), and a strong loss of heterozygosity (LOH) for human leukocyte antigen (HLA), with 67 deleterious mutations. The patient achieved partial radiological remission after a cycle of systemic chemotherapy with albumin-bound paclitaxel combined with nedaplatin. After radical resection of the left renal tumor, postoperative pathology confirmed complete tumor remission and tumor-like xanthogranulomatous pyelonephritis. Conclusion: This renal squamous cell carcinoma patient responded to systemic chemotherapy with paclitaxel combined with platinum, providing a reference for the future treatment of similar cases. Pathology and gene sequencing indicated that renal squamous cell carcinoma occurred in a background of active inflammation and that the tumor evolved immune escape mechanisms such as loss of HLA heterozygosity, with gene repair defects and TMB-H.

Collecting Duct Carcinoma of the Native Kidney in a Renal Transplant Recipient

Collecting duct carcinoma (CDC) is a rare and aggressive form of renal cell carcinoma (RCC) arising from the epithelium of Bellini's duct. It presents earlier in life and has a poorer prognosis than the clear-cell type. Historically, immunosuppressed renal transplant patients are more likely to develop malignancies than the general population. We report a case of CDC of the native kidney in a 59-year-old man who initially underwent kidney transplantation five years before the time of presentation. To our knowledge, CDC in the setting of renal transplant and long-term immunosuppression has not been previously described.