Non Langerhans Cell Histiocytosis of the Rectum: Case Report and Review of the Literature

Histiocytosis is a condition resulting from the abnormal proliferation of dentritic cells of the mononuclear phagocytic system. Previously classified as Langerhans cell histiocytosis and non-Langerhans cell histiocytosis, and recently into 5 categories (L, C, R, M and H), it can be localized to an organ or have a systemic manifestation, affecting most commonly the bone, skin and lymph nodes. Gastrointestinal involvement is extremely rare especially for the non-Langerhans group. We report a rare case of a non-Langerhans cell histiocytosis affecting the rectum, manifesting as a large, nodular, ulcerated, continuous lesion found during a colonoscopy, in an elderly man with initial presentation of rectorrhagia and abdominal pain. The importance of this case report is to highlight the manifestations of digestive involvement by a non-Langerhans histiocytosis, in addition to the characteristic features of histiocytosis on trans-rectal endoscopic ultrasound.