Angiodysplasia is a term used to describe a collection of abnormal blood vessels within the gut. These are usually formed of abnormal capillaries where a small group of capillaries have become dilated and unusually prominent. The term angiodysplasia and telangectasia are often used to describe similar appearances of such blood vessels, however telangectasia may be associated with a number of specific conditions, such as following radiotherapy in radiation proctitis (or radiation to the oesophagus), in scleroderma and hereditary haemorrhagic telangestasia. The mechanism by which the two different but similar lesions arise is slightly different.

Both these lesions may arise anywhere in the gut but they are commonly seen in the caecum, at colonoscopy and in the stomach at upper GI endoscopy. They may cause bleeding, which because it is an ooze rather than a torrential large volume haemorrhage often goes unnoticed. Such bleeding may lead to anaemia.

Usually angiodysplasia and telangectasia may be treated endoscopically, if they arise within the reach of an area which an endoscope can reach. They are commonly treated using APC (argon plasma coagulation).