ABSTRACT
BACKGROUND: In the literature, there are some reports of cases interpreted as carcinomatous transformation in eccrine syringofibroadenoma (ESFA). RESULTS: We have studied five cases with a histological mixture of ESFA and carcinoma. The carcinoma had a partial squamous cell cytology in all cases. In two of them, there was partial poroma and porocarcinoma picture. However, the squamous cell parts had some features of porocarcinoma such as retiform configuration and funnel-like cavities with luminal carcinoembryonic antigen (CEA) positivity. Also, there was strong epithelial membrane antigen (EMA) positivity. Therefore, we interpret the cases as porocarcinomas with extensive squamous metaplasia. One case had a life-long precursor lesion with a histologic picture interpreted as ESFA, with progressing cytologic atypia. Another case had ectodermal dysplasia, a condition known to predispose to ESFA and a precursor lesion of long-standing, probably benign ESFA. In these two cases, we interpret the carcinoma as a secondary development in a benign ESFA. Three cases were otherwise healthy people with precursor lesions of 10-, 5-, and 2-year duration. We do not know for certain if the ESFA preceded the carcinoma in these cases but we think that it probably did. CONCLUSIONS: We recommend that diagnosed ESFA shall be completely excised or followed, in view of the risk of developing carcinoma.
