ABSTRACT
Adult-onset Still's disease (AOSD) is an uncommon disorder characterized by fever, polyarthralgia, elevated white blood cell count, and maculopapular rash, the histologic features of which have not been well known. A 54-year-old woman presented with fever, arthritis, and persistent pruritic lichenified rash. These cutaneous lesions showed unique histological features such as dyskeratosis with a peculiar, distinctive distribution in the upper epidermis and cornified layers with hyperkeratosis. In addition, dermal mucin deposition was increased, with inflammation and minimal fibroblast proliferation. The patient was diagnosed with AOSD according to the diagnostic criteria of Yamaguchi. Herein, we present an atypical form of AOSD showing distinctive clinical and pathological manifestations.