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Case 202 - Discussion

Hematopathology Case

 

Langerhans Cell Histiocytosis

  • Morphology

    • In early stage of lymph node involvement, the tumor shows predominantly sinusoidal pattern. In later stage, there is spillover into the paracortex, sparing the follicles

    • Tumor cells:

      • Cell size: large, epithelioid

      • Nucleus: round or oval, fine chromatin, “coffee bean” nuclear grooves

      • Nucleolus: inconspicuous

      • Cytoplasm: abundant, pale eosinophilic

    • Eosinophils: abundant, may produce microabscesses

    • Often with necrosis

  • Immunoprofile: CD1a+, Langerin (CD207)+, S100+, CD4+, CD68+

  • Electron microscope: Birbeck granules 

  • Differential Diagnosis:

    • Reactive histiocytosis: lack of atypia, eosinophilia and necrosis; CD1a−, S100-, CD68+

    • Rosai-Dorfman disease: emperipolesis, lack of marked eosinophilia and necrosis; CD1a−, S100+, CD68+

    • Melanoma: prominent nucleoli and intra-nuclear inclusion; S100+, HMB45+

    • Dendritic and histiocytic tumors: see table below

 

 

Follicular dendritic

cell sarcoma

Interdigitating

dendritic cell sarcoma

Histiocytic

Sarcoma

Langerhans Cell Histiocytosis

Origin

Mesenchymal

Monocyte-macrophage

Monocyte-macrophage

Monocyte-macrophage

EM

Numerous cytoplasmic processes & desmosomes

Complex interdigitating cellular junctions

 

Birbeck granules

CD1a

+

CD3

CD20

CD21

+

CD23

+

CD35

+

CD45

+/− (weak)

+

+/−

CD68

+/−

+/−

+

+

CD163

+/−

+

+

+

S100

+

+/−

+

Langerin

+

HMB-45

Lysozyme

+

+

+/−