Detection of human papillomavirus with low-risk chromogenic in situ hybridization probes in seborrheic keratosis-like lesions of the male genital tract.

Seborrheic keratosis (SK) most commonly occurs on the trunk of older individuals. However, lesions resembling SK have been reported at genital sites. In this situation, positivity for human papillomavirus (HPV) has been documented, mostly in female patients, suggesting that these are more akin to condyloma than SK. We aimed to characterize genital SK-like lesions in men, including HPV status assessed by chromogenic in situ hybridization. We retrieved 40 specimens from 37 patients. The average patient age was 47, and most lesions were from the penis (75%), less commonly groin (12%), perineum (8%), or scrotum (5%). When a clinical impression was available, it was condyloma in 54%, but SK in some (15%). Recurrence was found in 36% of patients with follow-up. Acanthosis and hyperkeratosis were uniformly present, and most (83%) had horn cysts. Low-risk HPV chromogenic in situ hybridization was positive in 75%. The pattern of positivity was subtle in most patients, with 66% displaying only punctate granules of cytoplasmic/nuclear staining (66%). The remainder showed staining of entire nuclei (17%) or a mixture of both patterns (17%). The extent of staining was evenly divided between focal, moderate, and diffuse (each 33%). Control groups showed HPV positivity in 11/13 conventional condylomas (10 having a component of punctate staining) and 0/11 non-condyloma male genital skin specimens. Lesions of the male genital tract may histologically resemble SK; however, considerable rates of HPV positivity, concurrent or metachronous condyloma, and clinical suspicion of condyloma support these being more akin to condyloma than usual SK.