Oral lichen planus (OLP) is classified among precancerous conditions, as it is considered a generalized state associated with a significantly increased risk of cancer. The objective of this study was to discuss ultra-structural aspects of OLP that could play a role in enhancing metastatic potential, thus worsening the prognosis in oral squamous-cell carcinoma (OSCC). We report four cases of microinvasive OSCC which have occurred in OLP patients. All of them were stage I tumors, with a mean thickness of 1.75 mm. Recent studies indicate a tumor thickness over 4 mm as predictive of nodal metastases, but within 6 mo, our four patients with OSCC arising from OLP developed lymphnodal metastases. Our findings suggest that OLP-related OSCC may have a worse prognosis because of increased metastatic potential; obviously, further investigation is required, but this preliminary evidence emphasizes that extremely careful management of OLP patients is mandatory, and in cases of OSCC arising from OLP, a more radical treatment is probably required.