Concurrent renal cell carcinoma and central nervous system lymphoma in a patient with autosomal dominant polycystic kidney disease

Objective: To report an unusual case of synchronous renal cell carcinoma and CNS lymphoma in a patient with autosomal dominant polycystic kidney disease (ADPKD). Case Presentation and Intervention: A 58-year-old woman presented with progressive right hemiparesis of 2 months' duration. A brain CT scan revealed multiple enhanced lesions in the basal ganglia and the right occipital lobe. CNS lymphoma was confirmed by a stereotactic biopsy. Polycystic kidneys and a right renal mass were found incidentally. It was decided to treat the patient with cranial radiotherapy and chemotherapy first. The patient achieved complete remission of CNS lymphoma after 3 months, but the renal mass remained unchanged. A needle biopsy of the renal mass revealed renal cell carcinoma and unilateral nephrectomy was performed successfully. The patient remained in complete remission at 6-year follow-up. Conclusion: The patient was treated successfully with a combination of chemotherapy, radiotherapy, and unilateral nephrectomy. This report highlights the need for clinicians to remain alert to the possibility of double malignancies while caring for ADPKD patients, especially when multiple unexplained manifestations exist.