Denture-Related Irritation Fibroma With Myxoid Change of the Anterior Hard Palate: A Clinicopathologic Case Report

Denture-related irritation fibroma is a common reactive lesion of the oral mucosa caused by chronic mechanical irritation; however, cases arising on the anterior hard palate and exhibiting prominent myxoid stromal change are rare. A 54-year-old man presented with a long-standing, pedunculated mass (16 × 20 × 11 mm) on the right anterior hard palate in the setting of long-term maxillary complete denture use. After an incisional biopsy revealed moderate epithelial dysplasia, the lesion was excised under local anesthesia with a 2 mm safety margin at the stalk and subperiosteal dissection. Histopathology revealed a fibrous nodule covered by stratified squamous epithelium with hyperkeratosis and acanthosis, and a well-demarcated area of myxoid matrix immediately beneath the epithelium. Alcian blue (AB) staining showed diffuse stromal positivity, and immunohistochemistry demonstrated a very low Ki-67 labeling index and broad-spectrum cytokeratin (CK-wide) negativity in the lesional stroma, with diffuse epithelial positivity as an internal control, supporting a diagnosis of denture-related irritation fibroma with myxoid stromal change. Postoperative healing was uneventful, and no recurrence was observed after denture adjustment and improvement of denture hygiene. In this report, we present a case of denture-related irritation fibroma with moderate epithelial dysplasia and prominent myxoid stromal change that had remained untreated and progressively enlarged over approximately 20 years.