Pigmented nail streak associated with Bowen's disease of the nail matrix

We described a 59-year-old male physician with Bowen's disease occurring on the nail matrix of his right 5th finger. The rapid growth of the pigmented nail streak accompanied by nail deformity led us to consider the possibility of subungual melanoma clinically. Histologic features, however, were compatible with those of Bowen's disease accompanied by melanocytes with melanin-rich long dendrites in the nail matrix. We speculate that his occupational exposure to X-rays for 25 years played an important role in the pathomechanism of the present case.