Unusual findings in common peripheral ossifying fibromas: transepithelial elimination and epithelial inclusion.

Abstract

Peripheral ossifying fibroma (POF) is by far the most common of the reactive fibro-osseous processes affecting the gingiva.1 Histologically, POF shows a wide spectrum, the types and patterns of calcification and ossification varying in both amount and appearance, mostly depending on the stage of development, although the diagnosis is straightforward nevertheless.1 Here we describe two rare findings in mature lesions of POF: transepithelial elimination (TEE) of bony sequestrae (case 1) and multiple inclusions of odontogenic epithelium in the intervening fibrous stroma (case 2). Our working hypotheses were that case 1 gave rise to florid pseudoepitheliomatous hyperplasia (PEH) that could have been potentially misdiagnosed as squamous cell carcinoma (SCC), whereas case 2 showed overlap of microscopic features with peripheral odontogenic fibroma (POdF), making the differential diagnosis challenging. This article is protected by copyright. All rights reserved.