Osler-Weber-Rendu syndrome is an inherited disorder characterized by recurrent bleeding of mucocutaneous telangiectasias. Argon plasma coagulation (APC) has been used successfully to treat lesions in the gastrointestinal tract. Here, we report a case of bleeding gastric telangiectasias with an unusual pattern of recurrence. A 71 year-old woman with known Osler-Weber-Rendu syndrome has been followed in our clinic for over four years. She has a long history of iron deficient anemia due to intermittent bleeding from gastric telangiectasias. Over the last three years, she has required periodic blood transfusions to maintain a stable hematocrit despite APC of these lesions every one to two months. Multiple telangiectasias were seen in the distal half of the stomach on initial endoscopy. An ulcer later developed due to aggressive cautery. During subsequent sessions, telangiectasias were seen radiating from the periphery of this ulcer. Despite repeated APC, these telangiectasias increased in size and new ones were seen in the ulcer bed itself. With further treatment sessions, these lesions became increasingly ectactic and numerous. During her most recent endoscopic sessions, these lesions continued to bleed despite long pulses of APC. Adherent clots were seen overlying previously treated telangiectasias. At this time, the patient required two units of packed red blood cells each week to maintain a hematocrit of 28 to 30%. Because of the failure of endoscopic therapy, the patient underwent laparoscopic partial gastrectomy with Billroth II anastomosis. The patient did well postoperatively and has not required any further blood transfusions. APC has been used successfully to treat vascular ectasias of the gastrointestinal tract. A recent report of a patient with Osler-Weber-Rendu syndrome documented a poor response of gastric telangiectasias to APC. Although similar results were observed in this case, we have documented progression of these lesions over fourteen endoscopic sessions. This progression may represent the natural history of evolution in response to APC and may lead to insights to more effective treatment of these lesions.[figure1]Figure