Recurrent gingival nodule mimicking oral focal mucinosis: A case report highlighting diagnostic challenges in peripheral odontogenic fibroma

Peripheral odontogenic fibroma (POdF) and oral focal mucinosis (OFM) are rare benign lesions that may affect the gingiva and exhibit significant clinical and histopathological overlap. POdF often clinically presents as a firm, asymptomatic gingival nodule, and occasionally lacks odontogenic epithelium histopathologically. OFM, a non-neoplastic lesion characterized by a hyaluronic acid-rich myxoid stroma, can present with a nearly identical clinical profile and very similar histologic findings, which complicates the diagnostic process. This report describes a 48-year-old female with a recurrent, asymptomatic gingival nodule initially suggestive of OFM. The lesion recurred after incomplete excision and was re-evaluated histologically. Despite the absence of odontogenic epithelial islands, additional histologic features that included elongated rete ridges, a perivascular plasmacytic infiltrate, and a myxoid/myxomatous stroma favored a final diagnosis of epithelium-depleted POdF. This case highlights the potential for misdiagnosis between POdF and OFM, especially in the absence of epithelial components. Accurate differentiation requires comprehensive histopathologic evaluation, considering not only the stromal characteristics but also the lesion's clinical course, recurrence pattern, and inflammatory profile. Awareness of this diagnostic pitfall is essential for ensuring appropriate management and follow-up of gingival lesions.