*3.2.1 Duplication cysts*

*Endoscopy in Small Bowel Diseases*

**Duplication cysts**

**Lym phangiomas**

**Inflammatory fibroid polyp**

**Neuroendocrine tumors**

**Ectopic pancreas** **Layer of origin**

**Varices** 3rd Anechoic, with Doppler

signal

signal

2nd, 3rd Hypoechoic/

3rd, 4th Hypoechoic,

**GIST** 2nd/4th Hypoechoic,

4th

2nd or 3rd

*Main ultrasonographic characteristics of duodenal lesions.*

**Lymphoma** 2nd, 3rd,

**Brunner gland hyperplasia**

**Table 2.**

3rd Anechoic with internal

2nd, 3rd Hypoechoic, homogenous, polypoid

Intermediate

heterogeneous

heterogenous, hypervascular

Iso/Hyperechoic homogenous (less then

lipoma)

septa, without Doppler

echogenicity/ hyperechoic

echotexture, with cysts or ducts inside, umbilication

Anechoic, without Doppler signal

3rd/ external **Echogenicity Size (mm) Border Malignancy** 

— Sharp,

— Sharp,

sometimes with five layers

serpiginous shape

Sharp Yes

Sharp No

— Sharp No

8–18 Indistinct No

< 5–20 Indistinct No

when benign

Any Sharp

Hypoechoic Can vary Irregular Yes

**potential**

No

No

Yes, when >30 mm, with cystic space or echogenic foci

standard [10]. As literature regarding duodenal SETs is scarce, there is no consensus about when to perform EUS-FNA, but as previously mentioned, EUS can perform poorly in diagnosing small lesions, so biopsies should be performed in all lesions that are considered suspicious (possible malignant or with malignity potential). All lesions of the fourth layer (muscularis propria) should be biopsied, as most gastrointestinal mesenchymal tumors (GIMTs) have these characteristics. Techniques to obtain deep biopsies, like "jumbo" or "buttonhole" biopsies, may have better outcomes than EUS-

**Metastasis** Any Hypoechoic Irregular Yes **Lipoma** 3rd Hyperechoic homogenous Can vary Sharp No

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;

FNA in submucosal lesions, but carry high risk of hemorrhage [9, 11].

**3. Lesions of the duodenal wall**

**3.1 Vascular lesions**

**76**

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 needed when the diagnosis is unclear.
