Track

Clinical Studies

Abstract

Accurate diagnosis of inflammatory oral mucositis can be challenging given the similar clinical features of underlying conditions including oral lichen planus (OLP), mucous membrane pemphigoid (MMP), and pemphigus vulgaris (PV). Biopsy for routine light microscopic evaluation is often utilized for diagnostic clarity, as classic histologic features have been described for each of these conditions. While direct immunofluorescence (DIF) is typically recommended in these cases for diagnostic confirmation, it is not always performed if histologic features are strongly suggestive of a particular condition. We reviewed the pathology records of patients with MMP diagnosed by DIF at a university's immunofluorescence laboratory between 2020 and 2024. Among the 82 MMP cases confirmed by DIF, 22% (n=18) had original pathology reports of “lichenoid mucositis” or “suggestive of LP”. A blinded review by a dermatopathologist of the hematoxylin and eosin-stained slides of these 18 biopsy specimens revealed that 78% had a band of lymphocytic inflammation, 33% had basal layer vacuolization, 22% showed focal basement membrane zone thickening, and 61% had an area of subepidermal split. These observations support the idea that while lichenoid features on histopathology are typically associated with OLP, similar findings are also frequently present in MMP specimens, underscoring the need for further diagnostic studies. Our review emphasizes the importance of DIF to distinguish between OLP and MMP, especially considering the relatively high percentage of MMP cases that have histologic features of lichenoid mucositis on light microscopy.