an inflammatory histiocytoxanthomatosus involving the dermis and subcutaneous tissue
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primarily affects the face; periorbital is the site of predilection (85%)
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indurated yellow-red nodules, often ulcerated
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frequently paraproteinemia (90%) – IgG (kappa or lambda)
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10% of patients develop myeloma
histology:
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Touton giant cells with various amounts of necrobiosis or hyalin necrosis and the presence of lymphoid nodules
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CD1a and S100 negative
ddx:
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NLD – facial and scalp lesions are exceptional
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subcutaneous GA – mainly in children and does not ulcerate
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Xanthoma Disseminata – large body folds are the main sites of predilection and do not ulcerate
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multicentric reticulohistiocytosis – severe arthropathy and lesions do not tend to ulcerate (histology – large histiocytes with “ground glass” cytoplasm and no necrobiosis)