An Unusual Association between Sweet's Syndrome and Metastatic Papillary Follicular Thyroid Carcinoma.

Sweet's syndrome (SS), or acute febrile neutrophilic dermatosis, is marked by fever, leukocytosis, and painful erythematous papules/plaques resulting from neutrophil migration and accumulation in the dermis. This condition has been associated with underlying hematologic as well as solid malignancies. We describe a unique case of SS in a patient with metastatic papillary follicular thyroid carcinoma and group A streptococcal pharyngitis. The distribution of the patient's SS rash was similar to the rash of neutrophilic dermatosis (pustular vasculitis) of the dorsal hands.