Clear cell acanthoma presenting as polypoid papule combined with melanocytic nevus.

We report on a case of clear cell acanthoma that developed above a preexisting melanocytic nevus. Although melanocytic nevi can be complicated by the presence of several different types of epithelial or appendageal tumors, there have been no reported case of clear cell acanthoma combined with a nevus. Interestingly, in this case the clear cell acanthoma had a polypoid configuration, an unusual finding.