Differences in dermoscopic findings between early and mature clear cell acanthoma

Abstract

Clear cell acanthoma (CCA) is a rare benign epidermal tumor that is difficult to diagnose by visual inspection. Conversely, its diagnosis by dermoscopy is relatively easy owing to the characteristic serpiginous arrangement of coiled vessels, sometimes described as the "string-of-pearls" formation. However, in few published reports, the dermoscopic diagnosis of mature CCA has been reported. Here, we report the histopathological and detailed dermoscopic findings of two CCA cases. Between these, one case was of early (~6 months) CCA exhibiting the characteristic vascular string-of-pearls formation, whereas the other was of a more mature (~10 years) CCA; although the latter case showed combined thick and thin white intersecting lines with large coiled vessels and/or red clods, it had the string-of-pearls formation. Thus, regardless of CCA maturity, the string-of-pearls formation was present. We propose that the combination of combined thick and thin white intersecting lines along with the vascular string-of-pearls formation reflecting large coiled vessels and/or red clods on dermoscopy is a diagnostic clue to mature CCA.

Soft, Erythematous Nodule of the Ankle with a String of Pearls Vascular Pattern: A Quiz

“…In fact, we confirm that regardless of CCA maturity, the dermoscopic “string of pearls” vascular pattern, reflecting large glomerular vessels and red clods, is a highly suggestive diagnostic clue to mature CCA. Furthermore, thin and thick white intersecting curved lines, as proposed by Iseki et al ( 13 ) as a typical sign of mature CCA, were also observed in the current patient ( Fig. 1B ).…”

“…Regarding vascular findings in mature CCA, vessels acquire a more coiled appearance, while maintaining their typical serpiginous arrangement. In fact, as already suggested by Iseki et al ( 13 ), mature CCA lesions, such as the one in the current case, as well as early CCA lesions, exhibit the typical vascular string of pearls formation. This makes diagnosis by dermoscopy relatively easy, even in longstanding, eventually ulcerated lesions.…”