In vivo cutaneous antinuclear antibody positivity in palisaded neutrophilic and granulomatous dermatitis.

Palisaded neutrophilic and granulomatous dermatitis (PNGD) is commonly associated with underlying systemic inflammatory and neoplastic diseases, infections, and drug reactions. In vivo cutaneous antinuclear antibodies (ANA) have been described in skin biopsies from patients with known autoimmune disorders, but not previously reported in the setting of PNGD. We present two patients with systemic lupus erythematosus (SLE) and histopathologically confirmed PNGD. Direct immunofluorescence (DIF) studies revealed in vivo cutaneous ANA positivity in both patients. DIF findings in the skin mirrored serum autoantibody results. ANA positivity in skin specimens is reported as highly predictive of systemic connective tissue diseases (SCTD), although specific testing is not currently recommended as part of the laboratory work-up or diagnostic criteria for these disorders. In this case report, positive ANA results in skin biopsies of PNGD reflect the serological findings and clinical evidence of SLE in both patients. In vivo cutaneous ANA positivity is an interesting and supportive finding in PNGD in the setting of SCTD.