MRI reveals different Crohn's disease phenotypes in children and adults.

• To our knowledge, this is the largest morphological comparative study available in the literature using MRI as the main diagnostic tool to compare adult patients and children with Crohn's disease. • Our study showed significant differences between adults and children: a higher prevalence of rectal and perianal fistulous disease (PD) in pediatric patients and an increased prevalence of PD in the presence of severe colon-rectum involvement. • The association of rectal and perianal disease implies a poorer clinical prognosis and a higher risk of disabling complications in pediatric patients.