Cutaneous adnexal neoplasms are rare tumors that display differentiation in different ways. The aim of this study is, to present embryonic developmental properties and to determine the way of differentiation of adnexal neoplasms by evaluating the immunohistochemical expression of various markers.

Forty-seven cases with adnexal tumors enrolled in this study. Histopathologic groups of these 47 cases were: 15 (32%) hair follicle tumors, 11 (23.4%) sebaceous tumors, 8 (17%) apocrine tumors, and 13 (27.6%) eccrine tumors. CK5-6, CK6, CK7, CK8, CK10, CK19, GCDFP-15, carcinoembryonic antigen, epithelial membrane antigen and S100 protein expressions were examined by immunohistochemical methods.

As a result of this immunohistochemical study it was concluded that the expression of CK5-6 and CK8 carries more importance than other markers in determining certain types of differentiation of hair follicle tumors. It was also determined that, epithelial membrane antigen expression is important for the diagnosis of sebaceous tumors and the markers like CK8, CK10 and carcinoembryonic antigen may aid for the same purpose as well. It was found that, GCDFP-15 as well as CK5-6 expressions are significant for apocrine tumors, and carcinoembryonic antigen reaction as well as CK8 positivity will aid in determining differentiation of eccrine tumors. The presence of similar CK6 expression in all kinds of adnexal tumors has demonstrated that this marker is useless in differential diagnosis.