# Pediatric Endoscopy, Update 2020
## 7 Endoscopic Ultrasound  
The indication for endoscopic ultrasound (EUS) in children is very rare as transabdominal ultrasound usually provides excellent views [108]. As during ERCP, particular attention should be given during esophageal intubation in order to avoid cervical esophageal perforation. If the procedure is at all necessary, the indications are the same as in adults [25; 26; 27; 28; 29; 109; 110; 111; 112]. Indications are: Staging and diagnosis of neoplasms in and around the upper and lower GI tract, detection of bile duct stones, and pancreatic diseases. Fortunately, pancreatic masses are an extremely rare indication for EUS in children. Surgical series demonstrate a difference in the histology of neoplastic masses in children compared to the adult population [113; 114]. In particular, solid pseudopapillary neoplasms and pancreatoblastoma, followed by pancreatic neuroendocrine tumors (pNETs), are more frequent. The reported incidence of pediatric neuroendocrine Tumors (NETs) ranged from 1.14 to is 5.40 per 1 million children [115]. The localization of NETs in children is different from NETs in adults. In children, NETs are most commonly found in the appendix with ranges from 87.5% to 91.3% [116; 117]. Pancreatic NETs are very uncommon. [PERSON] et al. [117] reported only five patients with pancreatic NET on a total of 483 patients (1.04%). However, they also revealed that in the pediatric population NETs are more often associated with a suspected tumor predisposition syndrome and showed that pediatric pancreatic NETs in particular are associated with genetic syndromes.  
In the diagnostic evaluation of pancreatic masses, EUS with biopsy is an important and safe procedure also in pediatric patients [118; 119]. In pancreatic biliary diseases, the main endosonographic findings were microlithiasis in 25.9%, chronic pancreatitis in 16.7%, and pancreatic tumors in 11.1% of the patients [120].  
Another indication of EUS is the characterization of stenosis and strictures in the gastrointestinal tract and the assessment of cystic structures such as duplications cysts or bronchogenic cysts. The use of the ultrasound mini probe or small caliber (7.4 mm diameter) EBUS scopes seems favorable for the diagnosis of stenotic or superficial processes in the gastrointestinal wall and for EUS in small children (<15 kg and <3 years). From the age of three years, standard radial or linear echoscopes can be used. EUS is useful for the characterization of subepithelial lesions. Rectal EUS can be used for diagnosis of malformations, fistulations with or without chronic inflammatory diseases, and staging of rectal neoplasms, although extremely rare in children [30; 121]. The number of EUS performed in children might increase in future due to technical developments and adaptation of the equipment.  
The use of interventional EUS has been described for drainage of pancreatic fluid collection [122; 123; 124; 125; 126]. In particular, [PERSON] et al. described their experience in EUS-guided drainage of walled off necrosis using fully covered self-expanding metallic stents in 21 children with a technical and clinical success rates of 100% and 95%, respectively [127; 128]. EUS-guided obliteration of portal venous collaterals with N-butyl-2-cyanoacrylate into feeding varies is possible, and an effective treatment for recurrent bleeding from varices that are not suitable for direct endoscopic treatment [129].