Abdominal computed tomography CT Figure A for cancer staging

Abdominal computed tomography (CT; Figure 2A) for cancer staging demonstrated right hydronephroureter, obstructed at the middle segment of the right ureter, and multiple osteoblastic bony metastases in the thoracolumbar spine. A technetium (99mTc) medronic inositol phosphatase whole-body bone scan also revealed multiple bony metastases. Considering that the patient had Stage IV prostate cancer (cT3bN0M1), he underwent bilateral orchiectomy. Ureteroscopy was performed concurrently to evaluate the cause of the right ureteral obstruction, revealing a stricture in the middle third part of the right ureter (Figure 2B). Ureteroscopic biopsy of the stricture site showed tumor cell infiltration, which was positive for cytokeratin (CK) AE1/AE3 and PSA and negative for CK7 and CK20. Both the tumor morphology and immunoprofile supported the prostatic origin of the discrete ureteral metastatic lesion (Figure 3). Because of the failure of retrograde double-J stenting, percutaneous nephrostomy and antegrade double-J stenting were performed. Percutaneous nephrostomy was removed a few days later after notable improvement of the hydronephroureter.
Discussion Prostate cancer is one of the most frequently diagnosed malignancies in men. Metastatic lesions are commonly observed in the bones, lymph nodes, lungs, and liver. Since Benejam et al described the first case in 1987, few cases of discrete ureteral metastatic lesions of prostatic origin have been reported in the past few decades. Several theories concerning the mechanisms underlying metastasis to the ureter have been proposed, including direct invasion of the tumor, lymphatic or hematogenous spread, or upon instrumentation. The clinical manifestation in our patient differs from that of patients with common prostatic metastasis. Abdominal CT revealed no definitive metastatic lymph node or direct tumor invasion. Moreover, the patient had no history of ureteral instrumentation. Presumably, this type of discrete spreading may be attributable to the segmental pattern of the lymphatic drainage system of the ureter, which has no direct drainage network from the region of the prostate gland. According to current consensus, the treatment for metastatic prostate carcinoma is hormone therapy, including medical or surgical castration. Chalasani et al reported a case of prostate carcinoma invading from the ureter to the renal pelvis and observed an unsatisfactory outcome after androgen deprivation therapy for the metastatic lesion. Nevertheless, our patient showed a favorable response to hormone therapy, because the metastatic ureteral lesion was undetectable at 6 months follow-up.