Abstract: SA-PO953

An Unusual Case of Renal Cell Carcinoma (RCC) with Sarcomatoid Changes in a Renal Transplant Allograft

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Saleem, Muhammad Omar, Augusta University, Medical College of Georgia, Augusta, Georgia, United States
  • Mulloy, Laura L., Augusta University, Medical College of Georgia, Augusta, Georgia, United States
  • Zayas, Carlos F., Augusta University, Medical College of Georgia, Augusta, Georgia, United States
  • Kapoor, Rajan, Augusta University, Medical College of Georgia, Augusta, Georgia, United States
Background

Renal transplant recipients are at a higher risk of developing RCC than general population. RCC in renal transplant allograft is unusual. We present a rare case of highly agressive RCC with sarcomatoid changes in an allograft.

Methods

A 69-year Caucasian female with CKD stage 5 due to Autosomal Dominant Polycystic Kidney Disease (ADPKD) received a preemptive deceased donor kidney transplant. She presented 2 years post transplant with persistent hematuria. CT scan revealed 3.4 x 2.9 x 2.3 cm hypo-enhancing structure concerning for malignancy in the transplant allograft in addition to multiple simple and hemorrhagic cysts in both native ADPKD kidneys. She underwent a percutaneous biopsy of suspicious renal allograft mass, which was negative for malignancy and revealed only bland myofibroblastic proliferation. A repeat biopsy, which was also negative for malignancy was done 2 weeks later to confirm pathological findings and to eliminate any sampling error. A plausible diagnosis of persistent hematuria from her native polycystic kidney ruptured cysts was made. She presented about a year later with significant weight loss of 25 lbs and anorexia for two months duration. Repeat CT showed significant increase in the size of renal transplant mass. A MAG3 scan showed a fistula formation from the allograft mass to ileum. Patient underwent an exploratory laparotomy and an en bloc resection including transplant allograft nephrectomy and ileo-cecectomy was performed. Histopathology showed poorly differentiated RCC with sarcomatoid changes of allograft invading into the bowel wall. Staging CT showed multiple pulmonary metastases as well.

Conclusion

Renal transplant patients are at increased risk of developing RCC of the native kidneys. RCC can occur in transplant allograft as well but incidence is extremely low. A tumor registry reported incidence as low as <0.01% in allograft. RCC with sarcomatoid changes is extremely rare and only a few cases have been reported. Patients with ADPKD have higher incidence of sarcomatoid changes in RCC (33% vs 1 to 5%) as compared to general population. Our case is an unusual scenario due to findings of extremely rare and highly aggressive form of RCC with sarcomatoid features in a transplant allograft. We suggest an aggressive approach to diagnose renal allograft mass particularly in patients with ADPKD.