Langerhans’ cellA group of conditions characterised by proliferation of Langerhans cells, a lymphoreticular cell. Langerhans cell aggregates are nodular—especially in the lungs—and variably accompanied by eosinophils, foamy cells, neutrophils and fibrosis.
Good if limited to a single system. Multi-system involvement carries a 10–20% mortality due to organ failure; 50–60% have chronic disease, 30–40% have long-term clinical remission.
Langerhans cell histiocytosis types
A lesion virtually exclusive to cigarette smokers, which is a form of smoking-related interstitial lung disease. Smoking cessation may lead to reversal of changes or evolution to pulmonary fibrosis and pulmonary hypertension.
Eosinophilic granuloma; solitary bone involvement—A lesion of younger patients that may affect any bone (except in hands and feet), most commonly the cranial vault, jaw, humerus, rib and femur.
Mimics Ewing sarcoma.
Multifocal unisystem LCH
Hand-Schüller-Christian disease, polyostotic eosinophilic granuloma; multiple bone involvement—A lesion that may affect the skin, accompanied by proptosis, diabetes insipidus or chronic otitis media or combination thereof, marked by a chronic course with waxing and waning symptoms.
Multifocal multisystem LCH
Letterer-Siwe disease; multiple organ involvement—A lesion that affects bone, lung and skin; while histologically indistinct, it is more aggressive than the other forms.
Poor if < 18 months at time of diagnosis, haemorrhagic skin lesions, hepatomegaly, anaemia, thrombocytopenia, bone marrow involvement.