Isolated gastrointestinal Langerhans cell histiocytosis in a 16‐month‐old child: A case report

Langerhans cell histiocytosis (LCH) is a rare disorder characterized by clonal proliferation of Langerhans cells, most often involving the skin or bone. Isolated gastrointestinal (GI) involvement is extremely uncommon in young children. We report a 16-month-old girl with a 1-month history of chronic vomiting, bloody diarrhea, and failure to thrive who was found to have GI-LCH without systemic involvement. She was started on standard LCH chemotherapy with a favorable clinical response. This case highlights the importance of considering LCH in infants/toddlers with unexplained GI symptoms and the utility of targeted molecular testing (e.g., BRAF mutation analysis) in guiding therapy.