Skin nontumor

Dermal granulomatous and necrobiotic reaction patterns

Necrobiosis lipoidica diabeticorum

Last author update: 1 August 2011
Last staff update: 22 February 2021

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PubMed Search: Necrobiosis lipoidica

Mowafak Hamodat, M.B.Ch.B., M.Sc.
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Cite this page: Hamodat M. Necrobiosis lipoidica diabeticorum. website. Accessed March 21st, 2023.
Definition / general
  • Atrophic, yellow depressed plaques, usually on legs of diabetic patients
Clinical features
  • Also associated with hypo and hyperthyroidism, inflammatory bowel disease and vasculitis
  • Atrophic, yellow depressed plaques, telangiectasia and active inflammatory edge
  • Chronic lesions may show ulceration and crusting
  • Solitary or multiple, often symmetrical in lower extremities in pretibial area
  • Involvement of penis with a lesion resembling chronic balanitis has been described
  • Rarely, squamous cell carcinoma may arise in chronic lesions
Clinical images

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Necrobiosis lipoidica diabeticorum

Microscopic (histologic) description
  • Epidermal changes may be inconspicuous or absent; variable acanthosis, atrophy or hyperkeratosis
  • Palisading, necrobiotic granuloma consist of a large confluent area of necrobiosis centered in the superficial dermis and subcutaneous fat
  • Usually epithelioid histiocytes, giant cells and sometimes a well formed granuloma
  • Eosinophilic, swollen or degenerate collagen appears hyalinised with surrounding infiltrate of lymphocytes and histiocytes
  • Linear infiltrate of histiocytes between collagen bundles; occasionally lipomemebranous fat necrosis
  • Blood vessel wall thickening with intimal proliferation and narrowing of the lumen; also mild to moderate perivascular lymphocytic infiltrate
  • Plasma cells are almost always present
  • Cholesterol clefts are rare
  • Loss of elastic tissue
Negative stains
Differential diagnosis
  • Granuloma annulare: mucin+, lysozyme+
  • Necrobiotic xanthogranuloma: head and neck of patients with paraproteinemia, not associated with diabetes
Additional references
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