Case ReportA case of asynchronous bilateral cancer of the oral commissure

In Western nations, lip cancer accounts for 15%–30% of all oral cancers; however, lip cancer is far less common in Japan, accounting for only 0.9%–3.6% of oral cancers (references ) [1-3]. Lip cancer usually occurs in the lower lip, and is rarely seen in the oral commissure [35]. Histologically, most cases are squamous cell carcinoma [6]. To our knowledge, only one case of bilateral squamous cell carcinoma of the oral commissure has previously been reported [7].