Prostate brachytherapy seed migration to a left varicocele

Purpose: To report a rare case of seed migration to a left varicocele after transperineal interstitial prostate brachytherapy with loose iodine-125 ((125)I) seeds.

Methods and materials: A 73-year-old man presented with a serum prostate-specific antigen level of 5.21 ng/mL, Gleason score of 7 (3+4), and clinical T1c adenocarcinoma of the prostate. The patient underwent transperineal interstitial prostate brachytherapy with loose (125)I seeds followed by external beam radiation therapy. Two weeks after seed implantation, a followup pelvic radiograph was obtained. One month after seed implantation, a pelvic computed tomography scan for postimplant dosimetric analysis was carried out. Subsequent ultrasound examination of the scrotum was undertaken.

Results: Two weeks after seed implantation, an anteroposterior pelvic radiograph showed that a migrated seed was overlapped by the scrotum. Postimplant pelvic computed tomography revealed that a seed had migrated to the left side of the scrotum. Subsequent ultrasound examination of the scrotum revealed that the patient had a left varicocele to which the seed had migrated. The patient had no symptoms related to the migrated seed.

Conclusions: This is the first report of seed migration to a left varicocele after transperineal interstitial prostate brachytherapy with loose (125)I seeds. For the present case, we suggest that the seed moved from the prostate to the left varicocele through the pelvic veins, bypassing the systemic circulation.