# Long-Term Outcomes After Kidney Transplantation in a Recipient With Birt–Hogg–Dubé Syndrome

## TL;DR

A patient with Birt–Hogg–Dubé syndrome successfully underwent kidney transplantation after treatment for renal cancer, with stable outcomes two years later.

## Contribution

This case report provides evidence that kidney transplantation is a viable treatment option for patients with Birt–Hogg–Dubé syndrome-related renal cell carcinoma.

## Key findings

- The patient had stable renal function and no recurrence of renal disease two years post-transplant.
- Use of mTOR inhibitors and belatacept in post-transplant immunosuppression may be beneficial due to the syndrome's pathogenesis.
- A minimum waiting period after tumor removal is recommended before considering transplantation for these patients.

## Abstract

Introduction: Birt–Hogg–Dubé syndrome is a rare autosomal dominant disorder caused by folliculin germline mutations. Renal cell carcinoma is the most serious manifestation of this condition occurring at a rate of 30%, often requiring nephrectomy. Although preserving renal function remains the central goal of management, the risk of end-stage renal disease remains high. Patients with other inherited renal carcinomas have been successfully transplanted in the past, but there is scarce literature regarding Birt–Hogg–Dubé syndrome and kidney transplantation.

Case Presentation: A 48-year-old male presented to our facility for evaluation of recurrent pneumothorax. Computed tomography of the chest revealed bilateral pulmonary cysts and multiple bilateral renal masses. Given the coexisting pulmonary cysts and renal masses, he was diagnosed with Birt–Hogg–Dubé syndrome. Bilateral radical nephrectomy was performed due to the presence of multifocal tumors measuring up to 5 cm. Tumor pathology was consistent with oncocytoma and renal cell carcinoma. After 2 years of hemodialysis and surveillance, the patient underwent kidney transplant. At 2-year follow-up after transplantation, renal function remains stable and has no evidence of recurrent renal disease, managed with belatacept and mTor inhibitors.

Discussion: Tumor aggressiveness, metastasis risk, and time in remission are important factors when evaluating a patient with a history of Birt–Hogg–Dubé syndrome associated with renal cell carcinoma for kidney transplant. Therefore, these patients are suitable candidates for transplant after a minimum waiting period. Posttransplant immunosuppression with mTOR inhibitors can be considered since the mutation of the tumor suppressor folliculin germline in the mTOR pathway is central to Birt–Hogg–Dubé syndrome pathogenesis.

Conclusion: In this case report, we demonstrated that kidney transplantation is a viable option for patients with Birt–Hogg–Dubé syndrome–related renal cell carcinoma.