Langerhans cell histiocytosis (LCH) is a group of idiopathic disorders characterized by the proliferation of specialized,bone marrow-derived langerhans cells and mature eosinophils.The clinical spectrum ranges from an acute,fulminant,disseminated disease called LettererSiwe disease to solitary or few,indolent and chronic lesions of the bone or other organs called eosinophilic granuloma.Involvement of the gastrointestinal tract is very rare in LCH.We present the case of a 53-yearold woman referred by her primary care physician for a screening colonoscopy.A single sessile polyp,measuring 4 mm in size,was found in the rectum.Histopathological examination revealed that the lesion was relatively well circumscribed and comprised mainly a mixture of polygonal cells with moderate-to-abundant pink slightly granular cytoplasm.The nuclei within these cells had frequent grooves and were occasionally folded.Immunohistochemical staining was positive for CD1a which confirmed the diagnosis of LCH.On further workup,there was no evidence of involvement of any other organ.On follow up colonoscopy one year later,there was no evidence of disease recurrence.Review of the published literature revealed that LCH presenting as solitary colonic polyp is rare.However,with the increas-ing rates of screening colonoscopy,more colonic polyps may be identified as LCH on histopathology.This underscores the importance of recognizing this rare condition and ensuring proper follow-up to rule out systemic disease. Langerhans cell histiocytosis (LCH) is a group of idiopathic disorders characterized by the proliferation of specialized, bone marrow-derived langerhans cells and mature eosinophils. Clinical spectrum ranges from an acute, fulminant, disseminated disease called LettererSiwe disease to solitary or few, indolent and chronic lesions of the bone or other organs called eosinophilic granuloma. Involvement of the gastrointestinal tract is very rare in LCH.We present the case of a 53-yearold woman referred by her primary care physician for a screening colonoscopy. A single sessile polyp, measuring 4 mm in size, was found in the rectum. Histopathological examination revealed that the lesion was relatively well and formed mainly a mixture of polygonal cells with moderate-to-abundant pink slightly granular cytoplasm. The nuclei within these cells had frequent grooves and were occasionally folded. Immunohistochemical staining was positive for CD1a which confirmed the diagnosis of LCH.On f urther workup, there was no evidence of involvement of any other organ .On follow up colonoscopy one year later, there was no evidence of disease recurrence. Review of the published literature revealed that LCH presenting as solitary colonic polyp is rare. However, with the increas-ing rates of screening colonoscopy, more colonic polyps may be identified as LCH on histopathology. This underscores the importance of recognizing this rare condition and proof proper follow-up to rule out systemic disease.