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Home > E. Pathology by systems > Skin > interstitial granuloma annulare

interstitial granuloma annulare

Tuesday 31 January 2006


- assessed under low power
- increased number of inflammatory cells in the dermis separated by connective tissue mucin
- inflammatory infiltrate composed of lymphocytes and histiocytes
- inflammatory cells around blood vessels and between collagen bundles.
- no well-defined areas of necrobiosis

Differential diagnosis

- interstitial granulomatous drug reaction

  • eosinophils (+)
  • lichenoid changes at dermoepidermal junction
  • true necrobiosis rarely noted

- interstitial granulomatous dermatitis

  • neutrophils and neutrophil fragments
  • histiocytes, lymphocytes & eosinophils
  • palisades of histiocytes around basophilic collagen fibres