Necrotizing sialometaplasia (NSM) is a benign, self-limiting inflammatory condition of the salivary glands. Its clinical and histological resemblance to malignancies, such as squamous cell carcinoma and mucoepidermoid carcinoma, requires careful differentiation. While NSM predominantly affects the hard palate, its occurrence in atypical sites like the retromolar trigone is exceedingly rare and presents a significant diagnostic challenge. We report a case of NSM in a 30-year-old female presenting with a painful, indurated ulcer on the retromolar trigone. The lesion developed following a periodontal flap operation, suggesting an iatrogenic ischemic etiology. Despite an initial clinical suspicion of SCC, an incisional biopsy revealed extensive coagulative necrosis and prominent squamous metaplasia of the minor salivary glands. The diagnosis was confirmed by key histopathological features: the preservation of the underlying lobular architecture and the absence of cytologic atypia. The patient was managed conservatively, with complete resolution within six months. This case underscores the necessity of including NSM in the differential diagnosis of persistent gingival ulcers. Accurate histopathological recognition is paramount to avoid misdiagnosis and subsequent unnecessary, aggressive surgical intervention.

• 이득연(경북대학교 치과대학병원 구강악안면외과학교실) | Deuk-Yeon Lee (Department of Oral and Maxillofacial Surgery, Kyungpook National University Dental Hospital)
• 신창걸(경북대학교 치과대학병원 구강악안면외과학교실) | Chang-Geol Shin (Department of Oral and Maxillofacial Surgery, Kyungpook National University Dental Hospital)
• 최소영(경북대학교 치과대학병원 구강악안면외과학교실) | So-Young Choi (Department of Oral and Maxillofacial Surgery, Kyungpook National University Dental Hospital) Corresponding author