• Onset is usually between 5 and 10 years of age, but can be from birth.
  • Develops in <20% of patients with eosinophillic granuloma
  • Skeletal and visceral involvement with a chronic course
  • Minority of cases can be fatal
  • Classic triad of exophthalmos, diabetes insipidus, and rarefied defects of skull occurs in less than 10% of patients
    • Exophthalmos is caused by retro-orbital invasion
    • Diabetes insipidus caused by sphenoid invasion
  • Reticulo-nodular pattern of pulmonary involvement often observed
  • Other evidence of dissemination: anemia; splenomegaly; lymphadenopathy; and involvement of pericardium, liver, and retroperitoneum.
  • Skin involvement can occur as well, leading to yellow nodules and ulcers on palate, gums, and vulva
  • Jaw involvement can lead to tooth loss