So-called multicentric pigmented Bowen's disease. Report of a case and a possible etiologic role of human papilloma virus.

Multicentric pigmented Bowen's disease (MPBD) is a bowenoid atypia in the genitocrural region with peculiar clinical appearances. A 36-year-old Japanese female patient showed a variety of lesions. Clinically the lesions on the external genitalia consisted of brown-black papillomatous eruptions, black discrete or confluent papules, and whitish macerated papules. Histologically only black papules showed bowenoid atypia, but whitish papules also showed transient bowenoid atypia. Electron microscopically, in all three kinds of the lesions, spherical particles with a diameter of about 50 nm were scattered or gathered together in the nuclei of the keratinocytes beneath the horny layer. These particles were morphologically similar to human papilloma virus. Based upon clinical, histologic and electron microscopic observations, MPBD may be regarded as a new entity, and a term such as multicentric pigmented viral papulosis may be rather preferable than MPBD.