Giant clear-cell acanthoma with keratoacanthoma-like changes: a case report.Dermatol Online J. 2006 May 30;12(4):11.

Clear cell acanthoma is a benign epidermal lesion with a variable clinical appearance and distinct histopathology features. Although, it is considered an entirely benign entity, few case reports describe unusual or atypical variants of clear cell acanthoma. We observed a case of a large clear cell acanthoma that also has features of a keratoacanthoma.

Polypoid clear cell acanthoma: case report.J Eur Acad Dermatol Venereol. 2000 Nov;14(6):511-2.

Clear cell acanthoma of Degos is a rare benign tumour of epidermal origin with distinct histological features. Clinically, clear cell acanthoma is characterized by a 'stuck on' appearance of a nodule or dome-shaped plaque that usually occurs on the legs of middle-aged or elderly persons. We observed an unusual case of polypoid clear cell acanthoma on the right thigh of a 58-year-old male.

Clear cell acanthoma presenting as polypoid papule combined with melanocytic nevus.Am J Dermatopathol. 1999 Feb;21(1):63-5.

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.

Clear cell acanthoma developing in epidermal nevus.J Dermatol. 1997 Sep;24(9):601-5.

A 33-year-old Japanese woman presented with a black papule on a pigmented lesion which had been on her right thigh since her early childhood. A hematoxylin-eosin-stained section revealed a sharply demarcated, acanthotic epidermis composed of enlarged clear cells, which stained positively for epithelial membrane antigen and negatively for carcinoembryonic antigen. With antikeratin antibodies, the tumor cells stained for AE1 and AE3, but did not stain for CAM5.2. They contained abundant glycogen. Histologically, we diagnosed the case as a clear cell acanthoma which developed in the pre-existing epidermal nevus. This is the second such case in the literature.