Pleomorphic adenoma of the external auditory canal. An immunohistochemical and ultrastructural study.

Primary tumors arising from the glandular structures of the external auditory canal (EAC) are rare, with the majority arising from the ceruminous glands. The histochemical, immunohistochemical, and electron microscopic features of a pleomorphic adenoma of the EAC are presented; this is the seventh case reported. These studies confirm the key role of the myoepithelial cell in this tumor and include a correlation with pleomorphic adenomas in other sites.