Syringoid eccrine carcinoma: Report on two cases

Syringoid eccrine carcinoma is an uncommon, slowly growing, and locally aggressive primary eccrine adenocarcinoma, which rarely involves lymph nodes. The typical histological features of syringoid eccrine carcinoma consist of a tubulocystic proliferation in a dense fibrovascular stroma, invading the entire dermis and, in some cases, the subcutaneous tissues with perineural and arrector pili muscle invasion. Three distinct variants of syringoid eccrine carcinoma, a well-differentiated, a moderately differentiated, and a poorly differentiated carcinoma are identified. Two cases, respectively of moderately and poorly differentiated syringoid eccrine carcinoma, occurring on the scalp in two elderly women and showing a quite distinct clinical course, are presented. The first patient presented with a single lesion which had slowly enlarged without producing lymph nodal or visceral metastases. The second patient showed multiple nodules involving a wide area of the scalp and lymph nodal metastatic involvement. The cases reported underline the importance of a careful histological grading to properly address clinical staging and treatment.