Expression of p16 protein in lesional and perilesional condyloma acuminata and bowenoid papulosis: clinical significance and diagnostic implications.

BACKGROUND: The histopathological and clinical overlapping features between condyloma acuminata and bowenoid papulosis can present a diagnostic challenge and we sought to determine if immunochemistry can be helpful in this setting.

OBJECTIVE: In this study, we evaluate the specificity and sensitivity of p16 immunohistochemistry in condyloma and bowenoid papulosis lesions compared with uninvolved perilesional skin and discuss the possible clinical implications.

METHODS: A total of 36 skin biopsy specimens (24 samples of condyloma and 12 samples of bowenoid papulosis with adjacent uninvolved perilesional skin) were stained with an antibody to p16 protein.

RESULTS: In all, 75% of condyloma lesions showed sporadic and focal positive staining for p16 protein. All cases of bowenoid papulosis showed diffuse positive staining with p16 protein. Normal-appearing adjacent skin was negative in all cases.

LIMITATIONS: Studies with a larger number of cases are needed to confirm our data.

CONCLUSION: This immunostain has high sensitivity and specificity for the detection of bowenoid papulosis. Although p16 is expressed in both conditions, the staining pattern in bowenoid papulosis is strongly and diffusely positive involving the full thickness of the epidermis compared with the mostly focal or sporadic pattern observed in condyloma.