Prostate cancer is a significant cause of morbidity and death among men. While prostate cancer often metastasizes to common sites such as bone and liver, there have been rare cases of metastasis along the gastrointestinal tract. In this case report, we present an 85-year-old man who initially presented with altered mental status and later developed abdominal pain and tenderness leading to the discovery of duodenal ulceration. The biopsy of the ulcer was consistent with metastatic spread from the prostate. Involvement of the duodenum complicated both diagnosis and therapeutic management. This case highlights the possibility of unusual spread of prostatic metastases and further underscores the importance of early detection to guide treatment outcomes.