# Refractory Diarrhea Related to EPHB4 Mutation in a Patient With Capillary Malformation-Arteriovenous Type 2 Syndrome

## TL;DR

A rare genetic vascular disorder causes severe digestive issues, and a new treatment approach is suggested.

## Contribution

First reported case of CM-AVM2 with gastrointestinal involvement leading to malabsorption.

## Key findings

- Refractory diarrhea and failure to thrive in a CM-AVM2 patient were linked to GI tract abnormalities.
- Bidirectional endoscopy revealed telangiectatic capillaries and collagen deposition in the GI tract.
- Bevacizumab was trialed but ineffective; mTOR inhibitors may be a potential treatment.

## Abstract

Capillary malformation-arteriovenous type 2 syndrome (CM-AVM2) is a rare, genetic vascular disorder associated with abnormal capillary malformations and arteriovenous malformations. We present a case of CM-AVM2 with refractory diarrhea and failure to thrive due to aberrant, telangiectatic capillaries, and subepithelial collagen deposition found throughout the GI tract on bidirectional endoscopy. The patient was recalcitrant to standard therapies, so bevacizumab was trialed, but the patient expired. This is the first case of CM-AVM2 with diffuse GI mucosal involvement resulting in malabsorption. There is no treatment for this pathology, but treatment with bevacizumab or a mammalian target of rapamycin inhibitor may be efficacious.