Insights Into the Pathogenesis of Sweet's Syndrome

Sweet's syndrome, also known as Acute Febrile Neutrophilic Dermatosis, is a rare inflammatory condition. It is considered to be the prototype disease of neutrophilic dermatoses, and presents with acute onset dermal neutrophilic lesions, leukocytosis, and pyrexia. Several variants have been described both clinically and histopathologically. Classifications include classic Sweet's syndrome, malignancy associated, and drug induced. The cellular and molecular mechanisms involved in Sweet's syndrome have been difficult to elucidate due to the large variety of conditions leading to a common clinical presentation. The exact pathogenesis of Sweet's syndrome is unclear; however, new discoveries have shed light on the role of inflammatory signaling, disease induction, and relationship with malignancy. These findings include an improved understanding of inflammasome activation, malignant transformation into dermal infiltrating neutrophils, and genetic contributions. Continued investigations into effective treatments and targeted therapy will benefit patients and improve our molecular understanding of inflammatory diseases, including Sweet's syndrome.

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.

Multi-organ involvement of Sweet's syndrome: a case report and literature review

The hallmark of Sweet's syndrome (SS) is the infiltration of mature neutrophils in the upper dermis. We herein report a case of SS with multi-organ involvement. A 32-year-old man presented with fever, anemia and dyspnea. He was given antibiotics, without any improvements. Later, a number of erythematous lesions appeared, accompanied by deteriorating respiratory and cardiovascular functions. A diagnosis of SS was confirmed on a skin biopsy, and the patient was given corticosteroids, the dose of which was reduced after one month. The organ function subsequently deteriorated, and he ultimately died of multi-organ failure. Early recognition of SS with multi-organ involvement is important in patients with SS.