Langerhans’ cell

Langerhans’ cell

A 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.
Prognosis
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 
Pulmonary LCH
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. 
Unifocal LCH
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.
 
Imaging
Mimics Ewing sarcoma.
 
Treatment
Curettage.
 
Prognosis
Excellent.
 
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.
 
Prognosis
Relatively good.
 
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.
 
Prognosis
Poor if < 18 months at time of diagnosis, haemorrhagic skin lesions, hepatomegaly, anaemia, thrombocytopenia, bone marrow involvement.