This 73-year-old woman had a recent medical history significant for renal and bladder cancer, deep venous thrombosis of the right lower extremity, and anticoagulation therapy complicated by lower gastrointestinal bleeding. Colonoscopy during that admission showed internal hemorrhoids and diverticulosis, but a bleeding site was not identified. Five days after discharge to a nursing home, she again experienced bloody bowel movements and returned to the emergency department for evaluation. 