Langerhans Cell Histiocytoses

Question 1

Occurs in children less than 2 years of age
Manifests with multifocal cutaneous lesions that grossly resemble seborrheic skin eruptions, composed of Langerhans cells
Rapidly fatal if untreated
50% survive 5 years

Answer 1

Multisystem Langerhans cell histiocytosis (Letterer-Siwe disease)

Question 2

Expanding, erosive accumulations of Langerhans cells, usually within the medullary cavities of bones or less commonly skin, lungs or stomach
Any bone may be involved (commonly calvaria, ribs, femur)
May be asymptomatic or cause pain
Indolent and may heal spontaneously or treated by local excision
Usually affects children
Involvement of pituitary –> diabetes insipidus

Answer 2

Unisystem Langerhans cell histiocytosis (eosinophilic granuloma)

Question 3

Combination of calvarial bone defects, diabetes insipidus and exophthalmos

Answer 3

Hand-Schuller-Christian triad

Question 4

Potentially fatal hyperinflammatory condition
Mutations in gene important in the cytolytic secretory pathway that cause perforin and granzymes to induce apoptosis in target cells

Answer 4

Hemophagocytic lymphohistiocytosis/Hemophagocytic syndrome