Background: We report here an extremely rare case of cystosarcoma phyllodes of the seminal vesicle.
Methods: A 65-year-old man presented with urinary hesitancy, frequency and constipation. Clinical examinations including two needle biopsies were performed, and the patient had undergone open surgery.
Results: The final pathological diagnosis was cystosarcoma phyllodes of the seminal vesicle. Seven months after the operation, a chest X-ray showed lung metastasis, and the patient died 11 months after the operation.
Conclusion: To our knowledge, only one case of cystosarcoma phyllodes of the seminal vesicle has been previously reported.