Purpose or Case Report: * To present a rare case of rectosigmoid venous malformation in a 15-year old male patient without Klippel Trenaunay Syndrome.
* To review common syndromic and nonsyndromic causes of pediatric lower gastrointestinal bleeding with presentation of relevant imaging.
* To discuss the classic imaging features and various treatment options for colorectal venous malformations.
Methods & Materials: While preserving anonymity, we will present the imaging and clinical findings of a teenager with colorectal venous malformation who came to our institution with a two year history of anemia and intermittent hematochezia. This patient had an extensive workup including Meckel’s scan, upper endoscopy, colonoscopy, CT, and MRI. This patient had imaging features classic for a large venous malformation confined to the rectosigmoid and did not meet the clinical criteria for Klippel Trenaunay syndrome. Although there have been older reported cases of colorectal cavernous hemangiomas (a misnomer and term no longer preferred) without associated vascular malformation syndromes, nonsyndromic colorectal venous malformations are rarely reported.

We have also performed an extensive medical literature search for colorectal venous malformations, and syndromic and nonsyndromic causes of lower gastrointestinal bleeding in pediatric patients.
Results: We will present a case of colorectal venous malformation with lower gastrointestinal bleeding that had a delayed diagnosis. We will review the clinical and imaging features of colorectal venous malformations. We will also review other common causes of lower gastrointestinal bleeding in the pediatric patient with presentation of relevant imaging where applicable.
Conclusions: Colorectal venous malformations are an under recognized cause of gastrointestinal bleeding in the pediatric patient and therefore the diagnosis is often delayed resulting in patient morbidity. While colorectal venous malformations are often seen in the setting of vascular malformations syndromes such as Klippel Trenaunay, nonsyndromic colorectal venous malformations can occur. We hope that this case report will provide an educational review and increase awareness of lower gastrointestinal bleeding from underlying vascular malformations.