Disseminated eruptive clear cell acanthoma with spontaneous regression: further evidence of an inflammatory origin?

Clear cell acanthoma (CCA) is a benign epidermal lesion with distinctive clinicopathological features. Multiple disseminated eruptive CCA is an infrequent clinical variant that has been rarely reported. It is characterized by the presence of more than 30 lesions from 1 to 10 mm in diameter that appear progressively over the years. We report the case of a 65-year-old woman with multiple disseminated eruptive CCA affecting her lower extremities. In contrast to previous reports, most of the lesions appeared in a short period of time (less than a month) and, what is more interesting is that some of them have regressed spontaneously leaving residual hyperpigmentation. At present, the histogenesis and etiology of CCA remain unknown. Accumulating data suggest a reactive origin associated with a variety of different inflammatory conditions. The case presented in this report further substantiates that CCA is indeed a reactive epidermal reaction pattern with an inflammatory etiology.