(1) Fully developed lesions of Sweet’s syndrome are usually associated with prominent edema of the papillary dermis. However, this finding is not requisite for diagnosis. The diagnosis is made if the biopsy specimen shows an infiltrate of neutrophils and nuclear “dust” of neutrophils in the clinical context of erythematous papules and plaques situated on the face, the trunk, and arms, and accompanied by fever and leukocytosis.
(2) The patient presented here had high fever and leukocytosis. Therefore, acknowledging the fact that the skin lesions clinically are not prototypic for Sweet’s syndrome, the best diagnosis upon clinico-pathologic correlation still is that of Sweet’s syndrome.
(3) Histologic changes identical to these may be seen in an expression of pyoderma gangrenosum. In fact, a variety of systemic chronic inflammatory immune-mediated diseases can lead to skin lesions that are characterized by a nodular or interstitial dermatitis composed of neutrophils. Therefore, Sweet’s syndrome, rheumatoid neutrophilic dermatitis and pyoderma gangrenosum may be variants of a single reaction pattern.
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Prof. Kerl graciously provided clinical images and histologic samples.