Langerhans cell histiocytosis

Background

• Rare inflammatory or neoplastic process that can effect a number of organs, characterized by the granulomatous inflammation involving Langerhans cells (dendritic antigen-presenting cells)
• Most common under 15 years of age, but can present at any age

Clinical Manifestations

• Rash is most common feature, with general appearance similar to seborrheic dermatitis or atopic dermatitis (in children)
  • Scaly papules, nodules, plaques
  • May have petechiae, bloody crusting, or indurated nodules
• Bony involvement happens in most patients (80%)
  • Usually incidental
  • Usually solitary
  • Can involve skull, hip, pelvis, femur, or ribs
• Lung involvement is less common (20%)
• Lymphadenopathy in 30%
• Possibly hepatosplenomegaly
• Possibly infiltration of pituitary causing diabetes insipidus, with polyuria, polydipsia, and hypernatremia