Marginal Artery of Drummond Masquerading as a Fistulous Tract Resulting in Recurrent Lower Gastrointestinal Bleeding.

Lower gastrointestinal bleeding (LGIB) can be caused by a variety of causes. Pseudoaneurysms have been described as a rare etiology of LGIB and are associated with pancreatic pseudocysts that involve adjacent vasculature. Our study describes a 38-year-old man with recent severe coronavirus disease 2019 and necrotizing pancreatitis presenting with hematochezia and blood clots by gastrostomy-jejunostomy. Initial flexible sigmoidoscopy did not elicit an etiology for the LGIB. Recurrent hematochezia prompted colonoscopy and angiography, which demonstrated a pseudoaneurysm in the marginal artery of Drummond as the source. Our case highlights the importance of repeat evaluation of gastrointestinal bleeding of unknown etiology.