Deep Sweet Syndrome Secondary to Pegfilgrastim

Sweet syndrome, or acute febrile neutrophilic dermatosis, is a skin condition consisting of erythematous papules and plaques in association with fever, neutrophilia, and a neutrophilic infiltrate that typically involves the papillary dermis. Although development is most commonly idiopathic, medications are also frequently associated with the eruption, notably, the granulocyte colony-stimulating factor (G-CSF), filgrastim. Pegylated G-CSF, despite similar activity, is not commonly reported, with only four published cases. We present a case of drug-induced sweet syndrome with unique histologic features (deep inflammatory infiltrate) in association with the usage of pegfilgrastim in the treatment of invasive ductal carcinoma of the breast.