Elevated 18F-FDG Uptake in Skeletal Muscles Rather Than Cutaneous Foci in a Patient With Sweet's Syndrome.

A 64-year-old man was admitted to our hospital with a history of recurrent fever lasting 2 months. The initial physical examination for the patient showed normal cutaneous signs. An elevated uptake of tracer in skeletal muscles was observed by F-FDG PET/CT imaging. Three weeks later, a multitude of painful erythematous maculopapules appeared over his face, chest, and back. Pathological examination of a skin lesion showed papillary dermal edema with predominantly dense neutrophilic infiltrate in the dermis with no evidence of vasculitis, which was consistent with Sweet's syndrome.