Snapshot A 12-year-old boy presents to the emergency room for pain in in his right forearm with minimal trauma while playing tag. Radiography shows a fracture of the radius. A skeletal survey also shows 2 other lytic bone lesions on the cranium. He is referred to the pediatric oncologist for further workup and possible biopsy for a Langerhans cell histiocytosis. Introduction Overview login to view 2 more bullets Langerhans Cell Histiocytosis (LCH) Letterer-Siwe Hand-Schuller-Christian Hashimoto-Pritzker (Congenital Self-Healing Reticulohistiocytosis) Eosinophilic Granuloma Demographics < 2 years of age 2-6 years of age Neonatal period 7-12 years of age Pulmonary involvement seen in ages 30-40 years Involvement Skin, bone, and viscera pulmonary infiltrates, lymph nodules, liver, and spleen Skin, bone, and viscera liver, spleen, and lymph nodes Skin-limited Primarily bone > skin Pulmonary involvemen Prognosis Poor prognosis with disseminated disease Chronic and progressive Rapid spontaneous resolution is likely Good prognosis Epidemiology login to view 7 more bullets Pathogenesis login to view 4 more bullets Prognosis login to view 2 more bullets Presentation Clinical Presentation of LCH Letterer-Siwe Hand-Schuller-Christian Hashimoto-Pritzker (Congenital Self-Healing Reticulohistiocytosis) Eosinophilic Granuloma Symptoms Acutely disseminated lesions affecting the skin, bone, and internal organs Fever Bone pain Triad of diabetes insipidus, osteolytic bone lesions (cranium), and exophthalmos Skin lesions that crust and resolves spontaneously Solitary indolent bone lesions (cranium most common) with spontaneous bone fractures Physical exam Pink papules, pustules, vesicles, petechiae, purpura, and erosions on the scalp, flexural surfaces, and trunk Secondary impetiginization common Skin findings similar to Letterer-Siwe Multipe red to brown papulonodules, some with erosions Tenderness at site of bone lesions Other symptoms login to view 6 more bullets Imaging Bone radiograph login to view 4 more bullets Chest radiograph login to view 2 more bullets Studies Serum studies login to view 3 more bullets Urine studies login to view 1 more bullet Pulmonary function test login to view 1 more bullet Histology login to view 2 more bullets Electron microscopy login to view 1 more bullet Differential Multiple myeloma login to view 3 more bullets Treatment Medical login to view 17 more bullets Surgical login to view 3 more bullets Complications Bone fractures Spontaneous pneumothorax Infections Hearing impairment