Unanticipated Testicular Involvement in Prostate Carcinoma: A Case Report

Prostate carcinoma commonly metastasizes to distant organs; however, testicular involvement is exceedingly rare and may be overlooked in routine clinical practice. We report the case of a 78-year-old man with high-grade prostate adenocarcinoma who presented with a three-month history of painless hematuria and lower urinary tract symptoms (LUTS). Initial evaluation revealed a prostate-specific antigen (PSA) level of 11.01 ng/mL, and multiparametric MRI demonstrated locally advanced disease. A transrectal ultrasound (TRUS)-guided biopsy confirmed adenocarcinoma with a Gleason score of 10. Whole-body gallium-68 (⁶⁸Ga) prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET-CT) identified a PSMA-avid prostatic lesion with extension into the seminal vesicles and bladder, along with two focal PSMA-avid deposits in the left testis. Bilateral orchidectomy was performed, and histopathological evaluation confirmed metastatic prostate adenocarcinoma within the left testis. The confirmation of distant metastatic involvement prompted the intensification of systemic therapy with abiraterone and prednisolone, resulting in a decline in PSA to 4.63 ng/mL at four-month follow-up. This case highlights the importance of comprehensive staging in high-grade prostate cancer and demonstrates the clinical utility of PSMA PET-CT in detecting atypical metastatic sites such as the testes, thereby guiding appropriate surgical and systemic treatment decisions.