Clinical, dermoscopic and histopathological features of eccrine poroid neoplasms

Background: Eccrine poroma (EP) belongs to the group of benign adnexal tumors, but cases of eccrine porocarcinoma (EPC) arising on long-standing and untreated EP suggest a certain risk of malignant transformation. Objectives: To describe the clinical, dermoscopic and histopathologic features associated with different extremes in the spectrum of eccrine poroid neoplasms and to review the according literature. Methods: A retrospective analysis of patient characteristics and morphologic features associated with EP, EPC in situ and invasive porocarcinoma patients who attended two skin lesion clinics in Italy and Turkey between 2010 and 2011. Results: A total of 4 cases including 1 EP, 1 EPC in situ and 2 cases of invasive EPC in 4 patients were analyzed. Recent changes including bleeding, ulceration and sudden enlargement of a pre-existing lesion were associated with malignant transformation. Dermoscopically, polymorphous vessels consisting of coiled, hairpin and linear vessels were seen at all stages of progression. Histopathological findings of EPC in situ were limited to the epidermal component and were evident only at higher magnification. Conclusions: Clinicians and pathologists should carefully evaluate EPs with a recent history of change and erosion in order to avoid overlooking the potential development of EPC.