A 58-year-old Japanese man visited our clinic in December 2000 with a complaint of an erythematous plaque with reddish papules and pigmentation on the penis shaft and glans. He noticed the lesion 1 month before his visit. He denied any previous homosexual activity. His wife denied any genital skin lesion or gynecologic abnormality. No history of human immunodeficiency virus infection could be obtained. Physical examination of the skin lesion revealed an asymptomatic, flat-topped, approximately 10-mm-sized, reddish-brown keratotic plaque on the penis shaft. It showed an irregular surface, irregular border, and color variegation. Multiple, small, reddish-brown papules and plaques were distributed on the surrounding penis shaft and glans (Fig. 1). The patient had no symptomatic signs. No lymphadenopathy was noted in the inguinal area. A biopsy specimen revealed parakeratosis and an irregularly acanthotic epidermis composed of abnormal keratinocytes exhibiting cellular atypia and mitotic figures. The tumor cells had large, hyperchromatic, and pleomorphic nuclei (Fig. 2). These lesions were diagnosed as bowenoid papulosis (BP). For treatment, an operative excision with a 3 mm margin was performed. DNA was extracted from blocks of BP and non-BP, normal-looking skin tissue. Polymerase chain reaction (PCR) was performed utilizing L1 consensus primer set MY09 and MY11 (Bernard HU, Chan SY, Manos MM, et al . Identification and assessment of known and novel human papillomaviruses by polymerase chain reaction amplification, restriction fragment length polymorphisms, nucleotide sequence, and phylogenetic algorithms. J Infect Dis 1994; 170 : 1077-1085). MY09/11 consensus PCR generated an approximately 450-base-pair fragment from all of the samples (Fig. 3). Nucleotide sequencing revealed that the amplified L1 sequences were identical to that of human papillomavirus (HPV) type 16 (nucleotide positions 6582-7018). All of the L1 sequences from the BP lesion and the normal regions were identical. Our case contained the prototype sequence reported by Durst et al . (Durst M, Gissmann L, Ikenberg H, zur Hausen H. A papillomavirus DNA from a cervical carcinoma and its prevalence in cancer biopsy samples from different geographic regions. Proc Natl Acad Sci USA 1983; 80 : 3812-3815).