Clinical and Histopathologic Study of Apocrine-Type Mixed Tumor of the Skin.

ABSTRACT: Mixed tumor of the skin (MTS) is a tumor characterized by folliculosebaceous-apocrine differentiation. Because of the wide range of histological variations, understanding the unique features of MTS can help improve diagnosis. This study describes the histopathological characteristics of MTS, mainly apocrine-type MTS (AMT), using 166 cases of AMT. We found that nodular aggregates of myoepithelial cells, mucinous changes in the stroma, and follicular differentiation were standard characteristic features of MTS. Among the cases studied, 67% showed prominent follicular germinative cells and 40% showed prominent lipomatous metaplasia in the stroma. These cases often pose difficulties for the diagnosis of AMT because of insufficient evidence of sweat glands or myoepithelial cell differentiation. This is the first study to examine how the histological features of AMT change as the tumor extends deeper into the dermis. We found that the proportion of AMT with folliculosebaceous differentiation and large lumina increased as it got deeper into the dermis. Histopathological diagnosis of MTS is vital because the clinical symptoms lack specificity. This study enhances our understanding of the histopathological characteristics of MTS.

Immunohistochemical study of androgen, estrogen and progesterone receptors in salivary gland tumors

The aim of this work was to study the immunohistochemical expression of androgen receptor, estrogen receptor and progesterone receptor in pleomorphic adenomas, Warthin's tumors, mucoepidermoid carcinomas and adenoid cystic carcinomas of salivary glands. A total of 41 pleomorphic adenomas, 30 Warthin's tumors, 30 mucoepidermoid carcinomas and 30 adenoid cystic carcinomas were analyzed, and the immunohistochemical expression of these hormone receptors were assessed. It was observed that all cases were negative for estrogen and progesterone receptors. Androgen receptor was positive in 2 cases each of pleomorphic adenoma, mucoepidermoid carcinoma and adenoid cystic carcinoma. In conclusion, the results do not support a role of estrogen and progesterone in the tumorigenesis of pleomorphic adenomas, Warthin's tumors, mucoepidermoid carcinomas and adenoid cystic carcinomas. However, androgen receptors can play a role in a small set of salivary gland tumors, and this would deserve further studies.