Histiocytosis X; Langerhans cell histiocytosis; Eosinophilic granuloma; Pulmonary histiocytosis X; Nonlipid reticuloendotheliosis; Pulmonary Langerhans cell granulomatosis; Hand-Schuller-Christian disease; Letterer-Siwe disease
Histiocytosis is a general name for a group of syndromes that involve an abnormal increase in the number of immune cells called histiocytes.
There are three major classes of histiocytoses:
This article focuses only on Langerhans cell histiocytosis (histiocytosis X).
Histiocytosis X has typically been thought of as a cancer-like condition. More recently researchers have begun to suspect that it is actually an autoimmune phenomenon, in which immune cells mistakenly attack the body, rather than fight infections. Extra immune cells may form tumors, which can affect various parts of the body including the bones, skull, and other areas.
Some forms of the disorder are genetic.
Histiocytosis X is thought to affect roughly 1 in 200,000 people each year. It is most often seen in children ages 1 to 15. The rate peaks among children ages 5 to10.
Pulmonary histiocytosis X is a specific type of this disorder that involves swelling of the small airways (bronchioles) and small blood vessels in the lungs. It is most common in adults. The inflammation leads to lung stiffening and damage. The cause is unknown. It most often affects those ages 30 to 40, usually cigarette smokers.
Ladisch S. Histiocytosis syndromes of childhood. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 507.
Raghu G. Interstitial lung disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 92.
Lipton JM, Arceci RJ. Histiocytic Disorders. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 52.
© 2011 University of Maryland Medical Center (UMMC). All rights reserved.
UMMC is a member of the University of Maryland Medical System,
22 S. Greene Street, Baltimore, MD 21201. TDD: 1-800-735-2258 or 1.866.408.6885