Skin nontumor

Dermal granulomatous and necrobiotic reaction patterns

Interstitial granulomatous dermatitis

Topic Completed: 1 June 2011

Minor changes: 8 September 2021

Copyright: 2002-2021,, Inc.

PubMed Search: Interstitial granulomatous dermatitis with arthritis

Mowafak Hamodat, M.B.Ch.B., M.Sc.
Page views in 2020: 2,023
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Cite this page: Hamodat M. Interstitial granulomatous dermatitis. website. Accessed November 29th, 2021.
Definition / general
  • Uncommon; first described in 1993
  • Linear inflammatory indurations on lateral aspects of trunk (rope sign), also plaques or papules associated with systemic connective tissue disease
  • Usually in women
  • Arthritis is usually symmetric and involves fingers, wrists, elbows and shoulders
  • Associated with positive rheumatoid factor (not always), autoantibodies and elevated erythrocyte sedimentation rate
Case reports
  • Systemic corticosteroids
  • Dapson was useful in patients with rheumatoid papules
Clinical images

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Plaque on thigh

Microscopic (histologic) description
  • Diffuse dense inflammatory infiltrate of histiocytes within reticular dermis, focal degenerated collagen and elastic fibers, palisading histiocytes
  • Variable neutrophils, eosinophils, lymphocytes, mucin and vasculitis
  • Less mucin than granuloma annulare
  • Palisading of histiocytes and lymphocytes around a central zone of numerous neutrophils
Microscopic (histologic) images

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Superficial and deep perivascular and interstitial infiltrate of lymphocytes, eosinophils and histiocytes; histiocytes are scattered between collagen bundles and associated with mucin deposits

Positive stains
  • Direct immunofluorescence (DIF) may demonstrate C3, IgM and fibrinogen in dermal blood vessels
Differential diagnosis
  • Granulomatous drug reactions: vacuolar interface changes, often epidermotrophism of lymphocytes; resolves when drug is stopped
  • Interstitial granuloma annulare: mid dermal necrobiotic collagen center surrounded by palisading histiocytes, with fibroblasts and lymphocytes; occasional foreign body giant cells, vasculitis, mucin; may need multiple sections to find necrobiotic collagen
  • Necrotizing granuloma: may be due to infectious microorganism
  • Rheumatoid dermatosis: extensive homogeneous necrobiosis with numerous giant cells and stromal fibrosis
Additional references
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