Langerhans Cell Histiocytosis of the Gastrointestinal Tract – A Rare Entity

: Langerhans cell histiocytosis (LCH) is an idiopathic and rare disease that ranges in clinical severity based on location and organ involvement. LCH most commonly affects the skin and bones. The involvement of the gastrointestinal tract (GI) in adults is exceedingly rare and only 10 cases have been reported in the literature. We present the case of a 60-year-old male who was referred for a routine screening colonoscopy. Numerous 3-5 mm nodular lesions were present throughout the colon. A histopathological examination revealed diffuse aggregates of histiocytes within the lamina propria of the mucosa and immunohistochemical staining further confirmed the presence of Langerhans cells with a positive CD1-a stain. Although extremely rare, LCH involving the GI tract should be considered as a differential diagnosis when polyps or nodular lesions are witnessed on screening colonoscopies. In addition, the lesions must be biopsied to confirm the diagnosis of LCH and additional follow-up is essential to rule out systemic disease.