Nejm 1994;331:154
Cause:None are genetic
Pathophys:Spectrum from lethal Hand-Schüller-Christian (HSC) leukemia-like disorder primarily affecting infants to curable solitary lytic lesions of bone (eosinophilic granuloma [EG]). A monoclonal, probably neoplastic proliferation of histiocytes, which look like Langerhans’ giant cells; these invade lung, marrow, pituitary, liver, bone, and subcutaneous areas
Sx:Letterer-Siwe (LS): in infants only; rash
HSC: Youngest onset
EG: Oldest onset; often asx; or cough, weight loss, hemoptysis, chest pain
Si:
LS: papular/vesicular rash with white center and red rim, also on mucous membranes; lymphadenopathy; hepatomegaly; xanthelasmata, xanthomas, even infiltration into cornea; saddle nose
HSC: triad of (1) exophthalmus, (2) diabetes insipidus, (3) punched-out bone lesions
EG: localized often, eg, in lung, or in bone (esp head and pelvis); fever
Histocytosis X in adults (Nejm 2002;346:484), median survival = 12.5 yr from dx; die of respiratory failure; 60% mortality when occurs in infants.
LS rapidly fatal; HSC more slowly fatal;
EG, 50% recover, 50% progress
In all, diabetes insipidus in 40% by 5 yr (Nejm 1989;321:1157)
EG: spontaneous pneumothorax (10%) in pulmonary variety; skin invasion
Lab:
Noninv:PFTs in EG show obstructive and restrictive mixed pattern, impaired diffusion capacity; pO2 may be normal at rest but decreases with exercise
Path:Skin bx of rash shows histiocytes in LS; fibrosis, sclerosis, cholesterol phagocytosis in HSC; eosinophils in EG. Scalene node or lung bx even in asx patient will usually show diagnostic changes in EG
Xray:In EG, chest shows diffuse reticular pattern, bone survey shows lytic lesions