Subcutaneous Sweet syndrome in the setting of myeloid disorders: A case series and review of the literature

BackgroundThe association of neutrophilic dermatoses with myeloid disorders is well known, but neutrophilic panniculitis in the same setting has only been reported infrequently.ObjectiveWe aimed to better characterize these lesions clinically and histologically, and to provide a comprehensive differential diagnosis and appropriate diagnostic approach.MethodsThe pathology archives were searched for cases of neutrophilic panniculitis in patients with myeloid disorders. Clinical history and histologic features were studied. Similar cases in the English-language literature were reviewed.ResultsFive biopsy specimens from 4 patients and 11 previous case reports were identified. All patients presented with erythematous tender nodules typically involving the extremities. Most were accompanied by fevers, and resolved either spontaneously or with steroids. Histologically, the subcutaneous neutrophilic infiltrates demonstrated lobular or, less frequently, septal patterns with minimal dermal involvement. Leukocytoclasis, fat necrosis, reactive stromal fibroblasts, and mild reticular dermal edema were each seen in at least 3 of our 5 biopsy specimens. No myeloid blasts, vascular changes, or non-Miescher granulomas were observed. No micro-organisms were identified in the skin nodules.LimitationsThis study is limited by the small number of cases.ConclusionsBased on the fairly consistent clinical and histologic findings, neutrophilic panniculitis occurring in the setting of myeloid disorders is best classified as subcutaneous Sweet syndrome after exclusion of infectious panniculitis, id reaction, and leukemia cutis. These lesions may be associated with myeloid disorders, or induced by chemotherapy or other medications.