Rare Presentation of Prostate Cancer: Abdominal Pain Caused by Colonic Hematoma

Abstract

This is a case regarding rare presentation of metastatic prostate cancer involving gastrointestinal tract. Our case presents a 54-year-old Caucasian male with history notable for prostate cancer status post resection, adjuvant chemotherapy and 38 rounds of radiation. Previously on androgen deprivation therapy for bone metastases but stopped due to side effects. He presented to our tertiary care center with a chief complaint of severe right lower quadrant abdominal pain, as well as intermittent diarrhea. He denied melena, hematochezia, hematemesis, fevers, chills, or weight loss. Vitals signs were normal but abdominal exam demonstrated severe right lower quadrant pain with guarding, but no palpable masses. Prostate Specific Antigen (PSA) was elevated at 48 and Carcinoembyronic Antigen (CEA) level was 1.8. CT scan showed diffuse bowel thickening of the cecum and ascending colon, with stranding and questionable fluid collections, as well as new left lower lobe lung nodule. The patient underwent colonoscopy with negative biopsy, which was followed with explorative laparoscopy, omental biopsies, and hematoma drainage. Omental biopsies were positive for metastatic prostate cancer and hematology was consulted. Upon follow up with oncology, the patient was started on Bicalutamide, and three cycles of Docetaxel, which the patient tolerated well at the time of this submission. The main learning point from this case is that common diseases can present in unusual ways. While bone and lymph nodes are the most common locations for metastases from prostate cancer, there are other rare locations such as stomach, intestines, liver, and omentum. There are very few case reports that describe rare gastrointestinal manifestations of metastatic prostate cancer. When prostate cancer metastasizes to these rarer locations, patients can present with non specific symptoms which emphasizes the need to have a broad differential diagnosis. It is also important to take in the whole clinical picture and obtain an accurate history, which may help pinpoint a less common condition. Our patient had been off chemotherapy for an extended period of time, and had known bone metastases. Initial evaluation of our patient with colonoscopy was negative, but the need for further diagnostic evaluation required the patient to undergo explorative laparotomy to drain a hematoma, and eventually obtain proper tissue for diagnosis that helped determine his chemotherpay regimenFigure: CT scan showing Colonic thickening and fluid collection.