Langerhans cell histiocytosis involving the gastrointestinal tract.

Langerhans cell histiocytosis is a rare disease with a variable clinical presentation, and its prognosis and treatment depend on the extent and severity of disease. Although the pathogenesis of Langerhans cell histiocytosis has been debated in the past, recent evidence suggests that it is a neoplastic proliferation potentially derived from a myeloid-lineage precursor. Involvement of the gastrointestinal tract in Langerhans cell histiocytosis is exceedingly rare and is most often encountered in the pediatric population, in the setting of systemic disease. This is illustrated using a case of Langerhans cell histiocytosis involving the esophagus in a 59-year-old woman who presented with dysphagia, in which molecular testing documented a BRAF V600E mutation. We review the features and implications of this diagnosis.