Histiocytic Disorders

Definition of Histiocyte

  • Histiocyte is an Outdated Term Used to Describe Large White Blood Cells Which are Resident in Tissues: various cells may be classified as histiocytes
    • Dermal/Interstitial Dendritic Cells
    • Langerhans Cells
    • Monocytes/Macrophages

Classification of Histiocytic Disorders

Benign Disorders with Variable Biologic Behavior

Dendritic Cell-Related Disorders

  • Langerhans Cell Histiocytosis (LCH) (see Langerhans Cell Histiocytosis, [[Langerhans Cell Histiocytosis]])
  • Erdheim-Chester Disease (ECD)
  • Juvenile Xanthogranuloma (JXG)
  • Solitary Histiocytomas with Juvenile Xanthogranuloma Phenotype
  • Secondary Dendritic Cell Disorders

Macrophage-Related Disorders


  • Rosai-Dorfman Disease (RD): sinus histiocytosis with massive lymphadenopathy
  • Solitary Histiocytoma of Macrophage Phenotype

Malignant Disorders

  • Monocyte-Associated
    • Leukemias
      • Acute Monocytic Leukemia (M5A, M5B)
      • Acute Myelomonocytic Leukemia (M4)
      • Chronic Myelomonocytic Leukemia
    • Extramedullary Monocytic Tumor or Sarcoma
  • Dendritic Cell-Related Histiocytic Sarcoma: localized or disseminated
  • Macrophage-Related Histiocytic Sarcoma: localized or disseminated


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