Isolated Adult Gastrointestinal Tract Langerhans Cell Histiocytosis—Report of Two Rare Patients with Review of Literature

Langerhans cell histiocytosis is a rare disorder marked by monoclonal proliferation of Langerhans cells, primarily affecting the skin and bones. Isolated gastrointestinal tract involvement by Langerhans cell histiocytosis in adults is exceedingly rare, with only a few examples documented to date. Here, we report two patients with adult Langerhans cell histiocytosis with gastrointestinal tract involvement, accompanied by <i>BRAF</i> mutation analysis. Patient 1 was a 51-year-old man presenting with intermittent abdominal pain. Colonoscopy revealed five polyps, with histopathology and immunohistochemistry confirmation of Langerhans cell histiocytosis. <i>BRAF</i> testing was positive for the <i>V600E</i> mutation. Patient 2 was a 76-year-old woman, who presented with anemia and recurrent <i>C. difficile</i> colitis, leading to gastrointestinal distress and weight loss. Colonoscopy revealed two polyps which on pathologic evaluation were diagnosed as Langerhans cell histiocytosis. <i>BRAF</i> testing was negative. Both the patients exhibited benign clinical course with no multisystem involvement. Though Langerhans cell histiocytosis involvement of the gastrointestinal tract is uncommon in adults, it should be considered in differential diagnoses when histiocytic proliferation is observed.