[Squamous cell carcinoma arising in oral lichen planus : Report of two cases].

Lichen planus is a chronic inflammatory, immunologically mediated mucocutaneous dermatosis. Lichen planus mucosae predominantly affects the oral cavity. Various trigger factors such as bacterial or viral infections, drugs or physical stimuli are discussed in the development of the disease. An association with human papillomavirus infections has also been described, but is not sufficiently proven. Lichen planus mucosae is considered as a premalignant condition, but the malignant transformation rate is low. The risk of malignant transformation is significantly increased in patients with oral lichen planus who smoke, drink alcohol or have hepatitis C. We describe two patients with locally advanced squamous cell carcinoma that developed on a longstanding oral lichen planus. Both cases were successfully treated with radical tumor resection, subsequent tissue reconstruction, and adjuvant radiation/radiochemotherapy.