Long-time Survival of a Renal Transplant Recipient With Metastatic Mucinous Tubular and Spindle Cell Carcinoma: A Case Report.

BACKGROUND/AIM:Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a rare histological type of renal cell carcinoma (RCC). There are few reports of MTSCC occurring in renal transplant recipients (RTRs). The aim of this study was to report a case of long-term survival of a RTR with metastatic MTSCC of the kidney with sarcomatoid changes. CASE REPORT:A 53-year-old male with a left retroperitoneal tumor was referred to our department. He had been receiving hemodialysis since 1991 and underwent kidney transplantation in 2015. Computed tomography (CT) revealed suspected RCC, and a radical nephrectomy was performed in June 2020. Pathological findings revealed MTSCC with sarcomatoid changes. After the surgery, multiple metastases appeared in the bilateral adrenals, skin, para-aortic lymph nodes, muscles, mesocolon, and liver. We treated the patient with metastasectomy, radiation therapy, and sequential systemic therapy with tyrosine kinase inhibitors (TKI). Two years after the initial surgery, the patient died of cancer while controlling its progression. CONCLUSION:We report a RTR with aggressive and metastatic MTSCC with sarcomatoid changes, resulting in a longer survival time relative to multimodal therapy.