Esophageal strictures

Esophageal strictures in children are predominantly benign and associated with many conditions including reflux and eosinophilic esophagitis, caustic ingestion, tuberculosis, post surgical (anastomotic), IgG4‐related esophagitis, radiation and drug‐induced esophageal injuries (Figures 16.9 and 16.10).

In children with congenital esophageal stenosis, miniprobe EUS can distinguish between tracheobronchial remnants (TBR) and fibromuscular stenosis (FMS). In congenital esophageal stenosis with TBR, there are multiple echogenic regions in the muscle layer that represent aberrant cartilaginous remnants. Patients with TBR often require surgical resection because of the increased risk of perforation during dilation. In contrast, patients with FMS or membranous stenosis can be treated safely with esophageal dilation [12,23]. EUS is the best diagnostic test to distinguish between these conditions. High correlation between EUS miniprobe evidence of TBR and surgical findings has been documented [7]. Both high‐frequency miniprobe and three‐dimensional EUS have been used for preoperative evaluation of congenital esophageal stenosis in children [14]. After a pediatric endoscope is positioned just above the narrowed esophagus, the probe is inserted through the instrument channel and negotiated across the stricture. The miniprobe EUS procedure is performed using the direct contact method (Figure 16.11).

Other structural abnormalities of the esophageal wall and submucosal lesions such as esophageal duplications, malignant lesions, and lymphomas are generally well defined by EUS [30–33]. EUS is considered the primary diagnostic tool in preoperative staging of esophageal carcinoma.

Endoscopic treatment by mucosal EUS‐guided resection is used effectively to treat Barrett’s esophagus in adults. Barrett’s esophagus has no specific EUS characteristics but only a slight thickening of the mucosa. However, if complicated by severe dysplasia, it shows infiltration of the underlying layers and lymphadenopathy [34]. To study Barrett’s esophagus and other infiltrating lesions of the esophagus, it is necessary to utilize EUS at high frequency (e.g., 20 MHz).

EUS features of esophageal lesions are listed in Table 16.3.

Stomach

Many studies have shown that EUS is superior to CT in the staging of gastric tumors and associated lymph nodes. The information from EUS helps to indicate the surgical intervention, type of surgery, and any adjuvant chemotherapy. EUS assesses the degree of infiltration of the neoplasm in early and advanced stages. In pediatric patients it is very useful both in the rare cases of mass and of lymphoma.

Both the radial instrument and the miniprobe can be used in relation to age. Bowel or balloon filling is necessary for the study. Neoplastic lesions can infiltrate deeply into the gastric wall with complete disappearance of stratification [33] (Figures 16.12–16.14).

Congenital anomalies are common in children, for example duodenal duplication (Figure 16.15). In congenital duodenal duplications, EUS may identify anomalous pancreatobiliary ducts that may not be as well defined by CT scan or MRCP [26,27]. This information is essential for choosing between surgical and endoscopic therapy.

The plicate hypertrophy of the stomach is amenable to study by EUS for differential diagnosis with lymphomas (Figure 16.16).

In case of duodenal web, it is important to perform EUS before endoscopic dilation or dissection to evaluate the thickness of the web and the outlet of the biliary tract [33–35] (Figure 16.17).

EUS features of the main lesions of the stomach are detailed in Table 16.4.

Pancreatobiliary ducts

Given its high accuracy and sensitivity, EUS is particularly effective in evaluating pancreatobiliary diseases. One of the important benefits of EUS is a reduction of unnecessary diagnostic ERCP [10,29,30]. The diagnosis of lithiasis or microlithiasis of the common bile duct by EUS is superior to conventional ultrasound technique (Figure 16.18).

In children with chronic pancreatitis, EUS is more sensitive than CT scan, especially in the early stage of the disease, and helps to depict the focal or diffuse changes of the pancreatic parenchyma such as echogenic foci, interlobular septa, small cystic cavities, lobulated glandular margins, parenchymal heterogeneity, and pancreatic ducts/ectasia of collateral branches (Figure 16.19).

In children with pancreatic pseudocysts, it is often necessary to perform an internal drainage through the stomach (Figure 16.20). For a detailed description of pancreatic cystogastrostomy see Chapter 38. Complications related to this intervention (perforation or bleeding) can be prevented by EUS.

EUS with FNA allows precise histological analysis and differential diagnosis of cystic lesions/tumors of the pancreas and biliary ducts (Table 16.5).

Overall, current data support a high diagnostic value of EUS in many pancreatobiliary conditions including cholelithiasis, recurrent, chronic and autoimmune pancreatitis, idiopathic fibrosing pancreatitis, pancreas divisum, congenital anomalies, microlithiasis, pancreatic pseudocysts, and pancreatic mass lesions [19,35–43]. Therapeutic EUS with pancreatic fluid collection in children appears promising, although larger prospective studies will be needed for conclusion [44]. EUS and EUS‐guided interventions could alter clinical management in pediatric patients and should be considered in some challenging cases of pancreatobiliary disorders [45].

EUS is shown to be a safe and cost‐effective modality with both diagnostic and therapeutic capabilities in the pediatric population. It is now increasingly being recognized as a standard of care when evaluating pancreatobiliary conditions in children [40].