**3. Lesions of the duodenal wall**

### **3.1 Vascular lesions**

Anechoic SETs account for a large number of different possible diagnoses. Doppler-color ultrasonography is the best method to differentiate between vascular and cystic lesions. Vascular lesions in the duodenum are most frequently varices;

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*Endoscopic Ultrasound Assessment of the Duodenal Wall Lesions*

cyanoacrylate injection or coiling can be EUS guided.

other vascular malformations are rare. Varices are located in the third layer (submucosa) and are anechoic. Even in the absence of Doppler facilities, varices can be diagnosed by following their course, identifying other collateral vessels and perforating veins. Small varices can be compressed by the tip of the echoendoscope and misdiagnosed, so it is important to be careful. Therapeutic interventions like

Cystic tumors are liquid-filled cavities, hence anechogenic, that present in many different shapes and sizes. Many different lesions can present themselves as cystic or cystic-like. The most used classifications are simple cystic, polycystic or mixed

Cysts are rounded, unilocular and clearly delineated, with a completely anechoic content and dorsal enhancement. The most common diagnosis is a duplication cyst, which forms from a maldevelopment of the gut. Duplication cysts are located in the third layer (submucosa) and have a characteristic duplication of all the layers of the gut wall. They have a low risk of malignant transformation, or they can become symptomatic following increasing in size, infection or rupture. EUS-FNA is rarely

Brunner's glands are found in the duodenum and have an alkaline secretion, neutralizing stomach acid. Hyperplasia of these glands is usually asymptomatic, but can give a polyposis-like duodenum. The cause is thought to be excessive stimulation from excessive gastric acids, chronic inflammation or the decrease of pancreatic function. They are located mainly, if not exclusively, in the duodenal

Echoendoscopic appearance can vary as isoechoic or hyperechoic, sometimes with cysts inside. They arise from the third layer (submucosa) and much more rarely from the second one (deep mucosa). The diagnosis is based on biopsy result

Lymphangiomas consist of multiple dilated lymphatic vessels situated mostly in the third layer (submucosa), rarely in the second layer (mucosa). They are thought to be benign malformations of the lymphatic system that form a mass in the digestive tract. Lymphangiectasias, in contrast, are dilations of existing mucosal lymphatic vessels and described endoscopically as multiple small, white polyp-like elevations in the duodenum. They are mainly found in the small intestine, have a polyp-like appearance and are soft and easily compressible with a normal overlying mucosa. Most are asymptomatic; rarely, the size can cause obstruction, abdominal pain and hemorrhage [12]. As previously mentioned, they are formed from dilated lymphatic vessels, but also from smooth muscle fibers and connective tissue. Endosonographically they most often appear as polycystic. Their appearance varies vastly depending on the amount of smooth muscle and connective tissue. When they take up a large share of the lymphangioma it appears

*DOI: http://dx.doi.org/10.5772/intechopen.95927*

**3.2 Cystic and mixed lesions**

*3.2.1 Duplication cysts*

(with liquid and solid components) [8].

needed when the diagnosis is unclear.

*3.2.2 Brunner's gland hyperplasia*

bulb [5].

(**Figure 1**).

*3.2.3 Lymphangiomas*

inhomogeneous, rather than anechoic.

#### *Endoscopic Ultrasound Assessment of the Duodenal Wall Lesions DOI: http://dx.doi.org/10.5772/intechopen.95927*

other vascular malformations are rare. Varices are located in the third layer (submucosa) and are anechoic. Even in the absence of Doppler facilities, varices can be diagnosed by following their course, identifying other collateral vessels and perforating veins. Small varices can be compressed by the tip of the echoendoscope and misdiagnosed, so it is important to be careful. Therapeutic interventions like cyanoacrylate injection or coiling can be EUS guided.
