Abstract Background In pediatric ulcerative colitis (UC), atypical endoscopic findings at diagnosis, such as patchy inflammation and rectal sparing (RS), may be observed. However, few studies have examined whether these patients follow a similar clinical course to those with typical endoscopic findings. We retrospectively investigated the association between endoscopic findings at diagnosis and subsequent clinical course in pediatric UC patients treated at our institution. Methods We included UC patients aged ≤15 years at diagnosis who were seen at our hospital between April 1, 2018 and July 3, 2025, and whose histopathological findings were consistent with UC. Endoscopic findings at diagnosis were evaluated for the presence or absence of continuous inflammation (continuous vs. patchy groups) and for the presence or absence of RS. Patient backgrounds were compared between groups. Associations between these findings and time to initiation of corticosteroids or biologics after diagnosis were analyzed using the log-rank test and Cox proportional hazards models. Results A total of 51 patients were included (26 male, 25 female). The median age at diagnosis, duration from symptom onset to diagnosis, and PUCAI at diagnosis were 12 years, 83 days, and 35, respectively. Disease extent at diagnosis was pancolitis in 42 patients (82.4%), left-sided colitis in 7 (13.7%), and proctitis in 2 (3.9%). Endoscopically, 33 patients (64.7%) were in the continuous group and 18 (35.3%) in the patchy group; 8 (15.7%) had RS and 43 (84.3%) did not. Compared with the continuous group, the patchy group had significantly lower PUCAI, UCEIS, and CRP, and a significantly higher albumin level (all p 0.05). Time to initiation of corticosteroids and biologics was significantly longer in the patchy group (median 991 vs. 58 days for corticosteroids, and not reached vs. 358 days for biologics; both p 0.01). In a multivariable Cox model for biologic initiation including continuity status, UCEIS, and PUCAI as covariates, patchy inflammation remained independently associated with reduced biologic use (HR 0.33, 95% CI 0.11-0.96; p = 0.043). In contrast, RS status was not associated with differences in baseline characteristics or treatment initiation times. Conclusion In pediatric UC, the presence or absence of continuous inflammation at diagnosis appears to be an important factor. Patients with patchy inflammation tend to present with lower disease severity at diagnosis and follow a more favorable course, with longer intervals before requiring treatment with corticosteroids or biologics. Conflict of interest: Dr. Miyazaki, Haruka: No conflict of interest Uekado, Hiroki: No conflict of interest Aoyama, Yuichiro: No conflict of interest Kawase, Hina: No conflict of interest Shiraki, Aya: No conflict of interest Agawa, Misaki: No conflict of interest Nakamura, Hirotaka: No conflict of interest Ito, Yuki: No conflict of interest Okamoto, Norihiro: No conflict of interest Watanabe, Daisuke: No conflict of interest Ooi, Makoto: No conflict of interest Hoshi, Namiko: No conflict of interest Yamamura, Tomohiko: No conflict of interest Horinouchi, Tomoko: No conflict of interest Inoki, Yuta: No conflict of interest Kimura, Yuka: No conflict of interest Aoyama, Shuhei: No conflict of interest Pajimna, Jessica Aubrei: No conflict of interest Kodama, Yuzo: No conflict of interest
Miyazaki et al. (Thu,) studied this question.