S4666 Bleeding Small Bowel Arteriovenous Malformation in Cowden Syndrome: A Case Report

Introduction: Cowden syndrome is a rare disease caused by a PTEN gene mutation, resulting in multiple hamartomas with an increased malignancy risk. Few cases of arteriovenous malformations (AVMs) have been reported in patients with Cowden syndrome. This case presents a 48-year-old woman with Cowden syndrome and recurrent gastrointestinal (GI) bleed secondary to small bowel AVM. Case Description/Methods: A 48-year-old woman with Cowden syndrome presented with melena and hypotension. Workup revealed a hemoglobin (hgb) of 5.3 g/dl. Computed tomography angiogram (CTA) and esophagogastroduodenoscopy (EGD) did not reveal a source of bleeding. Despite stabilization efforts, she continued to have melena, prompting colonoscopy, tagged red blood cell scan, and video capsule endoscopy (VCE). These revealed small polypoid lesions, likely hamartomas consistent with Cowden syndrome, and hematin throughout the colon, but no source of bleeding. She stabilized after multiple transfusions and was discharged. Two weeks later, she returned with hgb of 4.6 g/dl and now requiring vasopressor support. Repeat CTA and EGD were again inconclusive. A second VCE localized bleeding to the proximal jejunum. Push enteroscopy found a visible vessel with adherent clot which was treated with epinephrine and clipping. She was discharged without further signs of bleeding. She presented again the following day with melena and hypotension. Repeat enteroscopy revealed blood within the proximal jejunum, prompting urgent embolization. Imaging during embolization noted findings consistent with a large AVM near prior clips. Unfortunately, symptoms returned yet again. Final EGD revealed a 5 cm oozing circumferential ulcer with mucosal congestion in the proximal tissue. She underwent resection of the affected segment and has not had recurrence of symptoms. Discussion: This case illustrates a rare but serious complication of Cowden syndrome – bleeding from small bowel AVMs. While hamartomas are well documented in Cowden syndrome, AVMs are exceedingly rare, with only a few reports, and just 1 previous case of upper GI bleed requiring surgical resection. Our case highlights the diagnostic and therapeutic challenges in identifying and managing small bowel AVMs in this population. Despite imaging, endoscopy, and embolization, only surgery achieved definitive hemostasis. This report emphasizes the need to consider vascular anomalies in patients with Cowden syndrome and unexplained GI bleeding and the value of multidisciplinary intervention when conservative measures fail.