Histiocytosis

LCH is the most commonly known form.

Incidence: 1:250,000 in children, with about a third of this incidence in adults.

Seen in all ages, but peak incidence is at 0–3 y of age.

Male:female ratio: 1.5:1.

Sporadic development with no established genetic predisposition.

Dependent on organ systems involved and extent of dysfunction

Specific organ dysfunction caused by infiltration with histiocytes, including liver, lungs, hematopoietic system, pituitary, spleen, and bone

Can involve single or multiple sites and organs

Treated with steroids and chemotherapy, which may cause adrenal insufficiency and result in the pt requiring stress steroids in the periop period

Central diabetes insipidus due to posterior pituitary involvement

Cervical instability if lesions present in cervical vertebrae

Severe pulm dysfunction possible; pulm Htn without overt right heart failure

A broad group of disorders involving infiltration of affected organs with monocytes, macrophages, and dendritic cells.

The most commonly discussed disorder is LCH, previously known separately as eosinophilic granuloma, Hand-Schüller-Christian disease, and Letterer-Siwe disease.

Severity of clinical symptoms varies markedly and can involve primarily skin and/or bone or liver, lung, or brain.

Can be limited or progressive and fatal. Younger children with multiple or severe organ involvement of “risk organs” (liver, lungs, spleen, hematopoietic system) have a high mortality.

Usual clinical presentation is in the first decade of life.

Pathophysiology is unclear and treatment is nonspecific.