LAUSR

(a) A 52-year-old woman presented with an 8-month history of a widening 2 5 mm pigmented streak on her left fifth fingernail. (b) Dermoscopy showed an inhomogeneous wavy streak with multiple depressed areas in the nail surface. The entire nail apparatus was excised. (c, d) Histopathological examination revealed acanthosis with a proliferation of atypical keratinocytes showing loss of polarity in the nail matrix with a moderate number of Ki67-positive nuclei throughout the keratinocytes. (e) Transepidermal elimination of tumour cell nests was seen in the nail plate. The diagnosis of Bowen’s disease (BD) was confirmed. This is the first report of nail BD with transepidermal elimination of tumour nests, which leads to a ‘woodgrain appearance’ on dermoscopy.