Atomic Accuracy: Unmasking a Colonic Dieulafoy Lesion With a Nuclear Medicine Scan.

Obscure gastrointestinal bleeding (OGIB) poses a unique diagnostic challenge as diagnosis may require repeat endoscopy, enteroscopy, video capsule endoscopy, contrasted imaging, or nuclear medicine (NM) scans. Dieulafoy lesions are enlarged submucosal vessels in a background of normal mucosa, typically found in the stomach, occasionally in the small bowel, and rarely in the colon. NM scans, although less common today, are sensitive to even very slow bleeding. We present a case of a critically ill 88-year-old male with persistent, episodic bleeding in whom an NM scan significantly aided in identifying a Dieulafoy lesion in the ascending colon.