Pigmented condyloma acuminatum.

We herein report a case of pigmented condyloma acuminatum in the genital region. A histopathological examination revealed keratinocyte proliferation, papillomatosis and basal pigmentation. Cellular atypia was rarely observed. The patient also had ordinary skin-colored nodules on the coronal sulcus. Polymerase chain reaction amplification with consensus primers for human papillomavirus (HPV) and subsequent sequencing confirmed an infection of HPV type 6. Pigmented condyloma acuminatum is not rare; however, making the differential diagnosis between bowenoid papulosis and seborrheic keratosis is sometimes difficult. The mechanism of pigmentation in such cases remains unknown and requires further investigation. HPV typing is a useful method for diagnosing the disease.