What characterizes Dieulafoy's lesions in the gastrointestinal tract?

Dieulafoy's lesions are characterized by the presence of a single, large, tortuous arteriole located within the submucosa of the gastrointestinal tract. These lesions are notable because they can lead to gastrointestinal bleeding, often without any accompanying ulceration or visible pathology in the mucosa itself. The large caliber of the arteriole can create a significant risk for hemorrhage, which can happen spontaneously.

In particular, Dieulafoy's lesions typically occur in the stomach but can also be found elsewhere in the gastrointestinal tract. Their distinctive feature of having a prominent arteriole is critical, as it contrasts sharply with other vascular lesions that may be composed of smaller vessels or different vascular structures. This uniqueness helps in the diagnosis and management of gastrointestinal bleeding, as recognizing the specific characteristics of a Dieulafoy's lesion can facilitate appropriate surgical or endoscopic interventions.