Solitary Testicular Metastasis from Prostate Cancer: A Rare Case of Isolated Recurrence after Radical Prostatectomy

Background: The prognosis of prostate cancer (PC) is mainly determined by the presence or absence of metastases. An isolated testicular metastasis of PC is rare. Case Report: A 71-year-old patient with PC presented with an increased serum prostate-specific antigen (PSA) level of 2.07 ng/ml two and a half years after radical prostatectomy. Assuming a local recurrence in the prostatic fossa, local radiotherapy with 64.8 Gy was performed. Unfortunately, the PSA level rose again, accompanied by a swelling of the left testis approximately one month after radiotherapy. A unilateral orchiectomy was then performed, presenting a testicular metastasis of the PC. After orchiectomy, the PSA decreased to <0.07 ng/ml. Two years later, the patient is still tumour-free. Conclusion: Careful clinical follow-up of patients with rising serum PSA level is important to recognize isolated, locally treatable metastastic disease. In particular, rare metastatic sites such as the testis or the epididymis should be taken into account before treatment of biochemical recurrence is initiated.