Prostate Carcinoma Metastatic to the Duodenum: A Unique Case

Abstract

Introduction: Early detection of prostate cancer by prostate specific antigen (PSA) monitoring and digital rectal examination results in good cure rates after surgery or radiotherapy. However, metastatic prostate cancer has a poor prognosis, with average survival rates of 1 to 3 years after diagnosis. Frequent sites for distant metastases are the bones and lymph nodes and rarely the lungs or brain. The involvement of gastrointestinal tract is very rare and only few cases of prostate cancer metastatic to the stomach have been previously reported in the literature. We report a unique case of metastatic prostate cancer to the duodenum. Case Presentation: A 67-year-old male with past medical history of metastatic poorly differentiated prostate cancer (Gleason score 4+5) diagnosed 4 years ago, history of deep vein thrombosis on warfarin presented for a syncopal episode with melena. He was also found to have obstructive jaundice. He had undergone a radical prostatectomy with subsequent radiotherapy for positive tumor margins and was placed on anti-androgen therapy. Laboratory studies showed alanine aminotransferase 718 U/L, total bilirubin, 7.7 mg/dL, direct bilirubin 5.7 mg/dL, alkaline phosphatase, 1643 IU/L and INR 6.1. The CT scan of the chest and abdomen revealed small peripancreatic lymph nodes and massive ascites along with contracted gallbladder with wall thickening. MRCP showed effacement of common bile duct and mild intrahepatic ductal dilatation. EGD and biliary EUS showed duodenal nodularity, periportal and peripancreatic lymphadenopathy. Biopsies from the duodenum showed a metastatic tumor consistent with the primary prostate carcinoma. Tumor cells were positive for prostate specific tumor markers. Patient underwent biliary stent placement and his LFts gradually improved and he was discharged for palliative care. Conclusion: Prostate cancer rarely metastasizes to the GI tract and there have been a handful of cases reported with metastasis to the stomach. We have recently reported one such case with simultaneous metastasis to the stomach and colon. Metastasis to the duodenum with biliary obstruction has not been reported in our search of the literature.