Condyloma acuminatum associated with syringocystadenoma papilliferum.

A 70-year-old man presented with a keratotic lesion of the right buttock. Histologic examination revealed an endophytic cystic and papillary lesion of the dermis. The papillae were lined by two layers of cuboidal epithelial cells with a dense plasmacytic infiltrate of the stroma, consistent with syringocystadenoma papilliferum (SCAP). The overlying epidermis showed acanthosis, papillomatosis, and hyperkeratosis. There were multiple foci of prominent koilocytotic atypia. In situ DNA probes for HPV type 6/11 were positive in many epidermal nuclei. The concurrent occurrence of SCAP and CA may be coincidental; however, the occurrence of CA may be related to the environment at the surface of the SCAP. Syringocystadenoma papilliferum often occurs in association with nevus sebaceus (NS), but it has also been reported from most body sites. When it is not seen in association with NS, the epidermis overlying SCAP may be hyperkeratotic or verrucous. The verrucous changes in our case had features of condyloma acuminatum (CA), which were confirmed by in situ DNA probes.