National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran TANAFFOS (Respiration) 1735-0344 1 3(summer) 2002 10 01 Infantile Histiocytosis X: Case Report 57 61 241574 EN Mohammad Reza Boloorsaz Department of Pediatrics, Abbas Mir-Afsharieh Department of Clinical Anatomical Pathology Kian Khodadad Oncology Unit, NRITLD, Shaheed Beheshti University of Medical Sciences and Health Services, TEHRAN-IRAN Makan Sadr Department of Pediatrics, Journal Article 2021 01 07 Langerhans cell histiocytosis (LCH) is a disease of unknown etiology that presents in three forms: Letterer- Siwe disease, Hand-Schuller-Christian disease, and Eosinophilic Granuloma. It is a multifocal disease that usually affects several organs and unifocal forms are rare. Pulmonary involvement occurs in approximately 40% of cases and almost always in young adults. Lungs are rarely affected in infant patients. This report presents a 15-month-old male infant that was admitted for cyanosis and respiratory distress. Diagnostic work up revealed a primary pulmonary histiocytosis and the treatment made a significant improvement of signs and symptoms by the time of discharge. (Tanaffos 2002; 1(3): 57-61) https://www.tanaffosjournal.ir/article_241574_ab4f4c5e769789dcc4228bdacdfecdc6.pdf