Local neutrophil and eosinophil extracellular traps formation in pyodermatitis pyostomatitis vegetans

Area of Science:

• Dermatology
• Immunology
• Pathology

Background:

• Pyodermatitis pyostomatitis vegetans is a rare inflammatory condition affecting skin and/or mucous membranes.
• Lesions can be erosive, granulomatous, keratotic with crusts, or pustular, commonly involving the scalp, face, trunk, extremities, and oral mucosa.
• It shares similarities with pyoderma gangrenosum, pemphigus vegetans, and pemphigoid vegetans, necessitating differentiation through unique histopathological findings.

Purpose of the Study:

• To elucidate the unique histopathological features of pyodermatitis pyostomatitis vegetans.
• To investigate the role of neutrophils and extracellular traps in the pathogenesis of this condition.

Main Methods:

• Histopathological examination of lesional skin.
• Analysis of direct immunofluorescence findings.
• Assessment of IL-36 expression and neutrophil extracellular traps (NETs) and eosinophil extracellular traps (EETs) in affected tissues.

Main Results:

• Histopathology reveals epidermal hyperplasia, focal acantholysis, dense inflammatory infiltrates, and eosinophilic microabscesses.
• Direct immunofluorescence is typically negative.
• Expression of IL-36, NETs, and EETs was observed in lesional skin, indicating their potential involvement.

Conclusions:

• Pyodermatitis pyostomatitis vegetans possesses distinct histopathological characteristics.
• Activated neutrophils and the formation of NETs and EETs are implicated in the innate immunity and autoinflammatory processes of the condition.