Isolated spermatic cord metastasis of prostate cancer after radiotherapy detected with ¹⁸F-PSMA PET/CT: a case report and literature review

We report the case of a 65 year-old male with prostate cancer previously treated with external beam radiotherapy and 2 years of androgen deprivation therapy. His nadir PSA reached undetectable level but gradually increased to 0.89 ng/dL. ¹⁸F-PSMA PET/CT demonstrated a PSMA-avid lesion at left spermatic cord. Left groin exploration revealed an 8 mm left vas deferens mass. Mass excision was performed and pathology result showed prostatic adenocarcinoma. The metastatic route is unknown but the possible routes are intraluminal route via ejaculatory duct, hematogenous route and lymphatic route. This case also highlights the role of ¹⁸F-PSMA PET/CT to detect a recurrent lesion at an atypical site in biochemical failure patients even at the low PSA level.