Abstract

Sweet’s syndrome, also known as acute febrile neutrophilic dermatosis, is an inflammatory febrile skin condition classically characterized by tender erythematous or violaceous nodules or plaques from the waist up with associated leukocytosis with or without elevated inflammatory markers. Histologically, Sweet’s syndrome is the prototype of neutrophilic dermatoses (a family of diseases with similar histopathologic findings including pyoderma gangrenosum, Behcet’s disease, neutrophilic eccrine hidradenitis, and others), and is characterized by a dense neutrophilic dermal infiltrate, leukocytoclasis without vasculitis, and dermal edema.Significant clinical variants (e.g. bullous Sweet’s syndrome, necrotizing Sweet’s syndrome) and histologic variants (e.g. histiocytoid, subcutaneous) exist.Sweet’s syndrome is a diagnosis of exclusion, and a thorough work up including a thorough history and physical examination, a tissue culture, and a sterile skin biopsy is necessary in order to exclude other more common disease mimickers, including infectious, neoplastic, and inflammatory conditions.

While most cases of Sweet’s Syndrome are idiopathic, other potential inciting factors can involve medication use, malignancy, infections, pregnancy, and coinciding autoimmune disease. The frequency of malignancy-associated Sweet’s syndrome varies widely, and most commonly involves hematologic, myeloproliferative, or myelodysplastic conditions. Given the complexity of inciting factors which have been associated with Sweet’s syndrome, research has been quite limited as far as analyzing the histopathologic features of Sweet’s syndrome and comparing its variations to each corresponding cause of disease in an effort to develop possible associations. Our study performs a histopathologic analysis and review of 66 previous cases at a tertiary care center from 2010-2022 which have been signed out as Sweet’s syndrome. With obtaining and reviewing each individual slide, we aim to review and compare each specific histologic feature with one another, and in turn work to develop potential associations of these features with the causes, subtypes, and clinical outcomes from each case.