Oropharyngeal hairy polyp with meningothelial elements.

The so-called hairy or teratoid polyp is a rare lesion of bigerminal origin that comprises elements derived from both ectodermal and mesodermal cell lines. In this article we report the presence of meningothelial elements in a hairy polyp, a previously undescribed component of this entity. The lesion was characterized by a pedunculated outgrowth from the hard palate. The surface of the outgrowth was covered by squamous epithelium and a central core of fibroadipose tissue, pilosebaceous glands, cleftlike pseudovascular spaces, and groups of epithelioid cells. These reticulated and cellular foci had the immunohistochemical and ultrastructural features of meningothelial tissue.