Late Metastasis of Renal Cell Carcinoma in Distal Femur Treated with Knee Joint Preservation: A Case Report.

Introduction: Late metastasis and recurrences after 10 years of curative treatment is a known biological behavior of renal cell carcinoma (RCC) and a long follow-up is required for the detection of metastasis. Late solitary bony metastasis is very rare. No case of a late solitary metastasis of distal femur, treated with wide local excision and reconstruction, is available in the literature. We present a case of solitary metastatic lesion of distal femur 12 years after radical nephrectomy for renal cell carcinoma in a 64-year-old male. Case Report: The patient presented to us with swelling in the right distal thigh for three years with a history of radical nephrectomy for RCC 12-years back. The lesion was not responding to local radiotherapy, and chemotherapy in the form of oral pazopanib, taken before orthopedic consultation. After core biopsy, the tumor was managed by intercalary wide local excision and reconstruction using a cement block and a lateral locking plate. Post-operatively, the histopathology report confirmed the diagnosis to be a clear cell tumor, consistent with metastatic RCC. The patient is independently mobile and tumor-free 2 years after the surgery. Conclusion: Wide resection and reconstruction of the skeletal defect remains the mainstay of the management of metastatic solitary lesion. We have presented a unique case of distal fem-oral solitary metastatic deposit from a primary RCC 12 years post radical nephrectomy treated by intercalary resection and reconstruction with bone cement-plate hybrid construct.