Acute febrile neutrophilic dermatosis in the setting of pembrolizumab in a patient with nonsmall cell lung cancer

Sweet syndrome, or acute febrile neutrophilic dermatosis is an inflammatory condition that may be idiopathic, paraneoplastic, parainflammatory, or drug associated. Recently, immune checkpoint inhibitors have been implicated in Sweet syndrome. Herein, we describe a patient with nonsmall cell lung cancer who developed Sweet syndrome in the setting of the immune checkpoint inhibitor, pembrolizumab. We also include a discussion of current literature of immune checkpoint inhibitors-induced Sweet syndrome and the histopathologic differential diagnosis of Sweet syndrome.