The Australasian journal of dermatology
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A 66-year-old woman presented with a 40-year history of a slowly enlarging erythematous patch on the left thenar eminence. Histopathology showed a sharp 'step' between the uninvolved and involved skin. Epidermal dysplasia and a cornoid lamella were not seen. These are the typical features of circumscribed palmar hypokeratosis.