When Phenotype Outspeaks Genotype: Uncommon Vascular Anomalies in Suspected Hereditary Hemorrhagic Telangiectasia Despite Negative Genetic Testing.

Hereditary hemorrhagic telangiectasia (HHT) is an inherited vascular disorder characterized by abnormal blood vessel formation involving the skin and visceral organs. Establishing the diagnosis can be challenging, particularly in the absence of classic clinical manifestations or confirmatory genetic findings. We report the case of a 42-year-old woman who presented with acute epigastric pain and was found to have extensive vascular abnormalities involving the liver, lungs, aorta, and mesenteric circulation. She had no history of recurrent epistaxis, mucocutaneous telangiectasias, or family history of vascular disease, and genetic testing for known vascular disorders was negative. Despite the absence of typical clinical and genetic features, the distribution and extent of vascular involvement raised a strong suspicion for underlying HHT. This case highlights the potential for a broader phenotypic spectrum of HHT and underscores the limitations of current diagnostic criteria and genetic testing approaches.