067 Comparison of histologic features in biopsies of patients with tumor necrosis factor-α-induced psoriasiform reactions and psoriasis vulgaris

Abstract

One of the most intriguing adverse reactions of TNF-α inhibitors (TNFis) is occurrence of de novo psoriasiform eruptions (TNF-psoriasis). Although well-accepted as a relatively common reaction of this medication class, many aspects of this side effect remain poorly characterized. Specifically, few studies have evaluated histologic features of TNF-psoriasis skin lesions, and most are limited by inclusion of few specimens. We comprehensively evaluated histologic features of 57 TNF-psoriasis biopsies from 50 unique patients seen at a single, tertiary care center dermatology department, and additionally compared histologic features of these biopsies to those of 85 biopsies from control patients with idiopathic psoriasis. The dominant reaction pattern in TNF-psoriasis biopsies was psoriasiform (80.7%), followed by spongiotic and pustular. Papillary plate thinning (p=0.03574) and neutrophils in the stratum corneum (p=8.89x10-7) were significantly more likely in histologic sections of idiopathic psoriasis compared to TNF-psoriasis. Alternatively, lack of parakeratosis (p=0.01983), neutrophils in the epidermis (p=0.01654), and eosinophils in the dermis (p=2.23x10-6) were significantly more likely in histologic sections of TNF-psoriasis compared to idiopathic psoriasis. Whereas eosinophils were present in the minority of idiopathic psoriasis specimens (17.6%) and no section had more than 3 eosinophils (n=1), 52.6% of TNF-psoriasis specimens displayed dermal eosinophils and 21.1% (n=12) had >3 eosinophils. There was no statistical difference in histological characteristics between the TNF-psoriasis cohort who responded to topicals compared to the cohort requiring more aggressive therapies. We believe consideration of these 5 contrasting histologic features can help dermatologists and pathologists confidently assess biopsies of psoriasiform lesions in patients treated with TNFis, and help drive more appropriate and effective treatment recommendations.