Endoscopic ultrasonography in submucosal lesions and extrinsic compressions of the gastrointestinal tract.

Endoscopic ultrasonography (EUS) provides an accurate exploration of the wall of the digestive organs, which makes it the procedure of choice for the diagnosis of submucosal lesions of the gastrointestinal (GI) tract. It reveals the exact origin of a lesion, whether it be inside or outside the gastrointestinal wall, and allows to define the characteristics of the lesion and help us to know its nature and make possible to perform EUS-guided fine-needle aspiration (EUS-FNA) to cytology with immunohistochemial analysis.