Reserve in Cleveland Ohio, their multi-institutional study on gastrointestinal (GI) tract involvement by Langerhans

cell histiocytosis (LCH). The authors highlight new insights from their large study showing that adult patients with

multisystem LCH exhibit similar clinicopathologic features to those of pediatric patients. Adults with single-system

LCH involving the GI tract have an excellent prognosis, whereas multisystem LCH occurring at any age carries an

unfavorable prognosis. High-risk features of GI LCH include pediatric age, GI symptomatology, noncolorectal GI

involvement, multifocal GI disease, nonpolypoid lesions, and infiltrative growth pattern.