Synchronous Bilateral Clear Cell Renal Cell Carcinoma With Multifocal Recurrence and Prolonged Disease Control Under Sequential Multimodal Therapy: A Case Report.

Abstract

Background: Synchronous bilateral renal cell carcinoma (RCC) is an uncommon clinical presentation that raises important diagnostic, surgical, and oncological management challenges. Colonic serosal metastases from RCC represent a particularly rare site of spread.

Case summary: We report the case of a 67-year-old man with synchronous bilateral clear cell RCC (ccRCC) who underwent staged nephrectomies in 2022, followed by early multifocal recurrence necessitating completion left nephrectomy, bilateral adrenalectomy, and segmental colectomy for serosal colonic involvement in October 2023. Pathology confirmed metastatic ccRCC at all resected sites. Adjuvant pembrolizumab was initiated post-resection but failed to prevent rapid systemic progression with bone and pulmonary metastases. Following adjuvant immunotherapy failure, the patient received three sequential lines of targeted therapy in the metastatic setting: sunitinib (first line), everolimus (second line), and cabozantinib (third line). Cabozantinib achieved a durable metabolic response, with complete resolution of nodal disease and partial response of bone and pulmonary lesions, despite prior multiline exposure. Treatment was complicated by medication-related osteonecrosis of the jaw, requiring temporary discontinuation; cabozantinib was reintroduced at a reduced dose (20 mg/day), which was associated with maintained disease control and acceptable tolerance. At the time of reporting, the patient remained on reduced-dose cabozantinib with chronic hemodialysis and hormonal replacement, maintaining an Eastern Cooperative Oncology Group (ECOG) performance status of 0.

Conclusions: This case illustrates the biological heterogeneity and unusual metastatic tropism of ccRCC, and underscores the clinical value of individualized multidisciplinary management; combining aggressive metastasectomy, palliative radiotherapy, and sequential targeted systemic therapy, in achieving meaningful long-term disease control while preserving quality of life.