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Skin-nontumor
Other dermatoses
Necrobiosis lipoidica
Reviewer: Mowafak Hamodat MB.CH.B, MSc., FRCPC, Eastern Health, St. Johns (Canada) (see Reviewers
page)
Revised: 1 August 2011, last major update August 2011
Copyright: (c) 2002-2011, PathologyOutlines.com, Inc.
Definition
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● Atrophic, yellow depressed plaques, usually on legs of diabetic patients
Clinical features
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● Also associated with hypo- and hyperthyroidism, inflammatory bowel disease and vasculitis
Clinical description
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● 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
Clnical images
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Micro description
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● 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
Micro images
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Negative stains
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● Lysozyme, mucin
Differential diagnosis
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● Granuloma annulare: mucin+, lysozyme+, and no association with diabetes
● Necrobiotic xanthogranuloma: head and neck of patients with paraproteinemia, not associated with diabetes
Additional references
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End of Skin-nontumor > Other dermatoses > Necrobiosis lipoidica
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