Seborrheic keratosis with bowenoid transformation: the immunohistochemical features and its association with human papillomavirus infection.

The bowenoid transformation of seborrheic keratosis (SK) has rarely been reported. The purpose of this study is to identify their diagnostic immunohistochemical features and association with human papillomavirus (HPV) infection. Skin biopsy specimens of the phenomenon were retrieved from 2001 to 2010. Benign SK, Bowen disease, bowenoid papulosis, and squamous cell carcinoma were included as controls. All specimens were stained for hematoxylin and eosin, Ki-67, p21, p16, p53, and cyclin D1. Polymerase chain reaction-amplified HPV DNA was analyzed. Seventeen cases of SK with bowenoid transformation were identified. The immunohistochemical pattern of bowenoid transformation was similar to that of Bowen disease and bowenoid papulosis. The malignant cells exhibited increased expressions of p16, p21, and ki-67 and a decreased expression of cyclin D1 (P < 0.01). HPV DNA was detected in 5 cases of bowenoid transformation. In conclusion, a portion of the cases of SK with bowenoid transformation were associated with HPV infection. Selective immunohistochemical stains were helpful in the diagnosis of malignant change in these cases.