Incidental Gastric Langerhans Cell Histiocytosis and Synchronous Adenocarcinoma of the Colon: An Interesting Case Report and Literature Review

Background/Aim: Langerhans cell histiocytosis (LCH) is an uncommon disorder characterized by an abnormal monoclonal proliferation of pathologic Langerhans cells. The clinical presentation of LCH is very unpredictable, ranging from single-system limited disease to severe multi-organ disease with a high mortality rate. LCH usually affects children and very rarely adults. The most common body parts affected by LCH are the bones, skin, lungs, pituitary glands, and lymph nodes. Gastrointestinal tract involvement by LCH is exceptionally rare, and only a few cases have been reported. Case Report: We present the case of a 50-year-old woman who was referred to our clinic by her primary care physician for an upper endoscopy and colonoscopy and was diagnosed with H. pylori–related gastritis and a synchronous gastric LCH and primary colonic adenocarcinoma. We describe the histologic characteristics and clinical implications of the LCH diagnosis. A review of the published literature revealed that LCH presenting as a gastric solitary lesion is rare. Conclusion: This case highlights the importance of recognizing this rare condition to ensure proper patient follow-up.