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Disorders of Langerhans Cells

Histiocytoses - large group of heterogenous disorders with evolving clinical and molecular classifications
  • Age, comorbidities and systemic findings influence the clinical course
  • Pediatric workup ruling out aggressive paraneoplastic outcomes is paramount
  • Derived from a common CD34+ hematopoietic precursor
 
Histiocytes - descriptive term used in pathology for mononuclear phagocytes residing in tissues (histio=”tissue”, cyte “cell”). Includes tissue macrophage or a dendritic cell. Group of cells that represent the immune system for the skin, includes:
 
Langerhans Cell Histiocytosis derive from Langerhans Dendritic Cells; Non-LCH disorders derive from interstitial dermal cells; Granulomatous disorders derive from macrophages and monocyte derived dendritic cells
Langerhans Cell Histiocytosis derive from Langerhans Dendritic Cells; Non-LCH disorders derive from interstitial dermal cells; Granulomatous disorders derive from macrophages and monocyte derived dendritic cells
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Life cycle of Langerhans cells. Note epidermotropism of immature Langerhans cell.
Life cycle of Langerhans cells. Note epidermotropism of immature Langerhans cell.
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Histiocytosis classification - new
  • Langerhans Histiocytosis
  • Cutaneous & mucocutaneous Histiocytosis
  • Rosai-Dorfman
  • Malignant
  • Hemophagocytic lymphohistiocytosis & macrophage activation syndrome
https://doi.org/10.1182/blood-2016-01-690636
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