A 64-year-old man was treated with brachytherapy for prostate cancer. Prostate-specific antigen (PSA) nadir was achieved at 3 months, while at 24 months PSA increased to 18.7 ng ml(-1). Re-biopsy and imaging revealed locally recurrent prostate carcinoma without metastasis. The patient was treated with salvage radical prostatectomy, and the surgical specimen underwent double-blind evaluation with RX scan and whole-mount histopathology sections. Radiology revealed an area without any seeds in the right base of the prostate, and pathologic assessment demonstrated adenocarcinoma involving the right base of the gland. This case is indicative of tumor relapse occurring for seed migration after good initial positioning.