Dermoscopic Features of Porocarcinoma: Report of 11 Cases and Review of the Literature

Porocarcinoma is a rare skin cancer that originates in cutaneous intraepidermal ducts of the sweat glands. Although dermoscopy is often helpful to make a diagnosis of skin tumors such as melanoma, dermoscopic features of porocarcinoma have not been investigated in detail. We aimed to identify dermoscopic features of porocarcinoma and to determine if they are distinguishable from other diseases. We examined the dermoscopic features of 11 cases of porocarcinoma, which were diagnosed using histopathological observations. Also, we reviewed previous case reports describing dermoscopic characteristics of porocarcinoma. Pink-white structureless areas were observed focally in all 11 cases. Ten cases showed polymorphous vascular patterns, in which two or more vascular patterns, such as linear-irregular, glomerular, dotted, and hairpin vessels, were present. None of the leaf-like vessels, coiled vessels, arborizing vessels, comedo-like openings, milia-like cysts, cerebriform patterns, or pigment networks were observed in any cases. In the previously reported 14 cases of porocarcinoma, the "white-to-pink halo" and the "polymorphous vascular pattern" were the most frequent dermoscopic findings (13 cases). "Pink-white structureless areas" was the third most common finding (11 cases). In cases displaying polymorphous vascular patterns, the main component was linear-irregular vessels (9 cases). Our 11 and 14 reported cases suggest that "pink-white structureless areas" together with "polymorphous vascular patterns" should be considered critical dermoscopic features of porocarcinoma. The findings could be helpful to distinguish porocarcinoma from tumors like eccrine poroma.