Palisaded neutrophilic and granulomatous dermatitis associated with ankylosing spondylitis.

Palisaded neutrophilic granulomatous dermatitis (PNGD) is a rare neutrophilic dermatosis that shows a broad clinical and histopathological spectrum. The clinical presentation of PNGD varies from asymptomatic papules, to nodules, to annular plaques. The most common clinical presentation is erythematous papules on the extensor surface of extremities, especially fingers and elbows. Histopathological findings demonstrate a spectrum of changes that reflect the evolution of the lesions, from only sparse mixed perivascular infiltrates to interstitial or palisaded granuloma formation with dermal fibrosis. The cause of PNGD is unknown, but there is a prominent association with systemic conditions, particularly with autoimmune diseases, representing rheumatoid arthritis and systemic lupus erythematosus, the most common associations. It has also been described associated to systemic sclerosis, sarcoidosis, systemic vasculitis, inflammatory bowel disease, and lymphoproliferative disorders, and also drugs have been implicated. Recently, it has been described the potential association with tumor necrosis factor alpha inhibitors. This dermatosis should be considered as a marker of systemic disease and particularly it should be considered in patients with history of autoimmune disorders who present with papular eruptions on the extremities.