Atypical Clear Cell Acanthoma

Abstract

Two cases of clear cell acanthoma (CCA) with marked signs of cellular atypia and mitotic figures are reported. Although the nature of CCA is not completely understood, it is considered to be a benign epithelial tumor. Our cases show that these lesions can develop malignant features.

Urachal duct remnant‐like umbilical clear cell acanthoma in an infant: An unusual presentation and pitfall in clinical practice

“…If dermatosis was the possible etiology, an underlying dermatosis would have been identified. As noted earlier, studies have proposed an association between an inflammatory reaction and CCA 8,21 . In the early days of an infant's life, local inflammation 28–31 and possible mild saprophytic infection 32–35 play important roles in the sloughing of the umbilical cord.…”

Clear cell acanthoma

“…Although CCA has been considered to have a benign course, there are two reports indicating a malignant potential 45,46 . Grunwald et al.…”

“…Grunwald et al. 45 reported two cases of ‘atypical CCA’ in 1991 with marked cellular atypia and mitotic figures, and Parsons et al. 46 reported a case of squamous cell carcinoma in situ arising within a CCA lesion.…”

“…10,42 Atypical clear cell acanthoma Although CCA has been considered to have a benign course, there are two reports indicating a malignant potential. 45,46 Grunwald et al 45 reported two cases of 'atypical CCA' in 1991 with marked cellular atypia and mitotic figures, and Parsons et al 46 reported a case of squamous cell carcinoma in situ arising within a CCA lesion. In the original article by Degos et al, they speculated that the malignant potential might be due to degenerative proliferative changes.…”

Clear cell acanthoma occurring on the hallux: the first case report

“…Unusual pathologic change of CCA may occur and microscopically shows syringomatous and naevus sebaceous‐like formations 8 . Atypical CCA showing marked cellular atypia and mitotic figures as well as squamous cell carcinoma (SCC) in situ arising within a CCA that was successfully treated with Mohs micrographic surgery have also been described 9,10 …”