The upper GI tract including the stomach and duodenum is also involved in CD. Upper GI endoscopy plays an important role in the diagnosis of pediatric CD. Lenaerts et al. reported the results of a retrospective study of CD in 230 children and adolescents with a mean age of 12.5 years at the time of diagnosis. During an average follow-up of 6.6 years, 30% of patients had lesions of the esophagus, stomach, and duodenum [7]. A prospective observational study of 56 children and adolescents with CD showed a high incidence (71%) of upper GI involvement [8]. In a study of childhood-onset IBD in Scotland (276 CD, 99 UC, 41 IBD of unclassified type, diagnosed before aged 17 years), at the time of diagnosis, CD involved the upper GI tract in 51% of cases, as well as the small bowel and colon in 51%, colon in 36%, and ileum in 6% [9]. A survey of a Belgian registry for pediatric CD also demonstrated a high frequency of upper GI involvement in pediatric CD patients [10]. The incidence of esophageal involvement in pediatric CD was ≤43%, while in adults it was only 0.2–11.2% [11]. Histopathological examination of the upper GI is useful for the diagnosis of CD. In comparison between 24 pediatric patients with CD and 28 age-matched patients without CD, histological abnormalities including noncaseating granulomas in the stomach and duodenum were more frequent in CD patients [12]. Hummel et al. also reported the importance of histopathological examination for the diagnosis of CD. In 11% of children with CD, diagnosis was based solely on granulomatous inflammation in the upper GI tract. Focal cryptitis of the duodenum and focally enhanced gastritis were found significantly more frequently in children with CD compared to those with UC and non-IBD [13]. Thus, discrimination between UC and CD may sometimes be difficult with ileocolonoscopy alone because of a lack of definitive lesions, especially in patients with newly diagnosed IBD and indeterminate colitis. Upper GI endoscopy should be performed as the first-line investigation in those patients.

Various endoscopic findings in the upper GI tract are observed in patients with CD. Solitary or longitudinal ulcers and erosions of the esophagus can be seen (Fig. 8.3). Intestinal Behcet’s disease can also involve the esophagus, therefore it should be ruled out. Aphthous erosions in the gastric antrum and bamboo-joint like appearance in the upper portion of the gastric corpus are often seen in CD [14] (Fig. 8.4a–f). Observation of the duodenum is also important for the diagnosis of CD. Various endoscopic findings including aphthous erosions, cobblestone appearance, and longitudinal ulcers are seen. Notch signs in the second portion of the duodenum are typical findings of CD (Fig. 8.5a–f).

Although there is no gold standard of IBD diagnostic criteria, several consensuses and criteria have been proposed [15–18]. As described above (Sect. 8.2.1), ECCO recommend ileocolonoscopy for the diagnosis of CD [2]. Although the diagnosis of CD should be performed comprehensively, typical endoscopic and radiological findings such as skip lesions with longitudinal ulcers and cobblestone appearance are important. In the diagnostic criteria for CD in Japan [19], longitudinal ulcer, cobblestone appearance, and noncaseating granuloma are defined as major findings. Aphthous lesions, anal lesions, and upper GI lesions are defined as supplementary findings. Hisabe et al. evaluated the Japanese diagnostic criteria for CD [20]. The survey included 579 patients with a definitive diagnosis of CD, and 59 with a suspected diagnosis of CD. In that survey, a total of 87.4% of definitive diagnoses of CD were based on the findings of longitudinal ulcer or cobblestone appearance. In the Asia–Pacific region, the importance of exclusion of infectious diseases, including intestinal tuberculosis, has been emphasized [21]. Understanding of typical endoscopic and radiological findings must be helpful to exclude various non-IBD diseases.