A Case of Pigmented Bowen's Disease.

Pigmented Bowen's disease is characterized by increased melanin pigment in the epidermis or papillary dermis, in addition to the typical findings of Bowen's disease. This disorder has been infrequently reported and it represents less than 2% of all cases of Bowen's disease. Thus far, there has been only 1 case of pigmented Bowen's disease on the umbilicus in the medical literature, and no such case has been reported in Korea. Pigmented Bowen's disease develops on sun-exposed areas of the face and neck, as well as sun-unexposed areas like the trunk, extremities, perianal area and umbilcus. A 36-year-old man presented with a 9-month history of solitary dark brown slithery or wavy plaque with a verrucous surface on the umbilicus, and the lesion measured 1 x 2 cm in size. The histopathologic findings showed hyperkeratosis, parakeratosis and atypical keratinocytes disorderly arranged throughout the epidermis. Increased melanin pigment was noted in the basal layer of the epidermis. From these findings, we diagnosed this lesion as pigmented Bowen's disease.