Oral squamous cell carcinoma arising from oral epithelial dysplasia shows high postoperative recurrence despite favorable histopathology.

OBJECTIVES: We sought to determine whether oral epithelial dysplasia (OED)-derived oral squamous cell carcinoma (OSCC) represents a clinically and pathologically distinct subtype, given that a substantial subset of OSCC is known to arise from OED. MATERIALS AND METHODS: This retrospective study analyzed 335 patients with OSCC treated at our institution. OED-OSCC was defined as OSCC in patients with a documented history of biopsy-proven oral epithelial dysplasia, irrespective of the specific clinical lesion. RESULTS: OED-derived OSCC (OED-OSCC), defined by pathologically confirmed dysplasia rather than clinical presentation, comprised 195 (58.2%) patients in the cohort. Compared with non-OED-OSCC, it demonstrated less aggressive tumor-centric features including shallower DOI, lower PNI, earlier T stage, and fewer nodal metastases, yet paradoxically greater cumulative surgical burden with more patients undergoing multiple resections. Recurrence in OED-OSCC was significantly associated with margin dysplasia, which was more frequent than in non-OED-OSCC (74.00% vs. 48.97%). Moreover, recurrence rates increased with margin dysplasia severity (mild: 60%; moderate: 73.08%; severe: 100%), underscoring that field cancerization at the primary site may contribute to the distinct clinical behavior of OED-OSCC. The clinical value of dysplasia-free margins warrants prospective evaluation, as even mild dysplasia was associated with a 60% recurrence rate. CONCLUSIONS: OED-OSCC represents a pathologically anchored subgroup in which margin dysplasia severity was associated with high recurrence despite favorable tumor-centric features. These findings support prospective evaluation of mucosal margin status in risk stratification. CLINICAL RELEVANCE: By anchoring OSCC classification to histopathologically confirmed dysplasia, OED-OSCC identifies patients with a dysplastic background and elevated observed recurrence risk who may merit enhanced surveillance.