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Abstract

Eosinophilic folliculitis is a folliculocentric eosinophil-rich dermatosis reflective of a Th2 dominant microenvironment and is seen in the setting of human immunodeficiency virus infection, atopy, iatrogenic immune dysregulation and hematologic malignancies, particularly B-cell neoplasms. A necrotizing pyodermatous variant, NEF was described in 2000 in 10 patients with a history of atopy and additional immune dysregulation related to drug therapy and autoimmune disease. It has been postulated to represent a more fulminant form of EF associated with progressive folliculocentric tissue pathergy to result in a morphology that can resemble early pyoderma gangrenosum We report a single case of NEF in an 82-year-old man with known B cell lymphoma who presented with erythematous, crusted nodules on the face. Three shave biopsies were performed. The biopsies demonstrated striking folliculocentric inflammation comprising eosinophils and neutrophils associated with  marked epithelial destruction, intrafollicular mucin deposition, perifollicular abscess formation and frank perifollicular neutrophilic dermolysis resembling folliculocentric pyoderma gangrenosum but with striking tissue eosinophilia. Special stains for microbial pathogens were negative. A diagnosis was rendered of NEF as a morphologic variant of the eosinophilic dermatoses of hematologic malignancy. In closing, NEF represents a distinct clinicopathologic entity within the EDHM spectrum. Neoplastic B cells and or TH2 cells in association with malignant B cells may be associated with certain eosinophil promoting cytokines such as IL-5, eotaxin, and IL-3. Given the excessive Th2 microenvironment key to lesional pathogenesis and progressive tissue pathergy, a drug such as dupilumab could prove to be very effective.