[Pigmented extramammary Paget's disease accompanied with condyloma acuminatum: a case report]

Pigmented extramammary Paget's disease (PEMPD) is an uncommon intraepithelial adenocarcinoma and a rare variant of Paget's disease, characterized as a superficial pigmented scaly macule clinically and an increased number of melanocytes scattered between the Paget's cells histologically. So it may be confused clinically and histologically with melanocytic tumors, dermatitis and other dermatoses. Different therapeutic attitudes are required in this case of adenocarcinoma in situ as opposed to melanoma and dermatitis. Condyloma acuminatum (CA) is a common sexually transmitted disease caused by human papilloma virus infection, which is also called as genital warts. In this article, we first reported a case of a 65-year-old Chinese man who had pigmented extramammary Paget's disease complicated with CA. This patient presented with verrucous papules on the scrotum for 3.5 years, infiltrative erythema with itch on the mons pubis for 3 years, and scrotum and penis involved gradually for 4 months. Physical examination showed a 8 cm×10 cm dark red patch on the upper part of the scrotum, penis and mons pubis, as well as few maculopapules and nodules. Histopathologic examination of the lesion on the scrotum revealed a focus of Paget's disease, characterized by the presence of large round cells with abundant pale or granular/dusty cytoplasm, pleomorphic vesicular nuclei and prominent nucleoli (Paget's cells), while the histology of the verrucous lesion was consistent with CA. Immunohistochemistry was performed, which showed diffuse positive staining with CK, CEA, PAS, CK20, EMA, CK7, and Ki-67 (40%), HER2 in Paget's cells and negative with P53, P16, CK5/6, S100, MelanA, HMB45, estrogen receptor, progesterone receptor, and gross cystic disease flid protein 15 (GCDFP15). Human papillomavirus-11 (HPV-11) was positive by genotyping using gene amplification in the lesion of scrotum. According to clinical features and laboratory findings, a diagnosis of PEMPD complicated with CA was made. Local excision of the lesion was performed and sent for histological examination, with all margins clear of tumor. Both aforementioned diseases often occur in the vulva. Even so, it has been rarely reported coexisting of the above two diseases, of which the clinical significance and association are also unclear. In this article, we also reviewed the literature relating to PEMPD, and on this basis, the profile of this disease is discussed including its pathogenesis, clinical manifestation, diagnosis, treatment and advances. Due to PEMPD occasionally accompanied with an underlying carcinoma, it's essential to make an accurate diagnosis. Besides, review of the literature reveals that pigmented variant of Paget's disease could be initially misdiagnosed as melanocytic tumors and other dermatoses unless the entity is considered in the differential diagnosis and additional confirmatory studies are performed.