Surveillance of Isolated Colonic Langerhans Cell Histiocytosis in an Adult: A Case Report.

Langerhans cell histiocytosis (LCH) is a rare disorder involving the proliferation of myeloid-derived dendritic cells. It most commonly affects children aged less than 1 to 2 years old. Langerhans cell histiocytosis in adults is more uncommon with an estimated incidence of 1 to 2 cases per 1 million. Langerhans cell histiocytosis can present as a multisystem or single-system disease involving bone, skin, lymph nodes, and various other organ systems. The spectrum of symptoms can range from asymptomatic disease, localized skeletal or dermatologic manifestations, or systemic symptoms of weight loss, fever, and other organ-specific manifestations. Langerhans cell histiocytosis with isolated involvement of the gastrointestinal tract is exceedingly rare with only approximately 14 cases reported in the English medical literature. Here, we report an additional case of LCH presenting as an isolated colonic polyp. This patient was also followed for a 3-year period after initial diagnosis to provide valuable follow-up data. With this case, we aim to contribute to the literature by further characterizing the presentation, treatment, and disease course of this rare phenomenon and provide valuable data to guide future screening guidelines for isolated LCH polyps in the colon.