Leukoplakia of the labial commissure

A white lesion located in the labial commissure can pose problems for both the clinician and the pathologist. The clinician may be limited in his surgical treatment because of aesthetic reasons, whilst the pathologist may be confronted with a lesion with or without candidal involvement, showing the histological features of hyperplastic candidiasis, verrucous hyperplasia, verrucous carcinoma, epithelial dysplasia, carcinoma-in-situ and, occasionally, squamous cell carcinoma. A retrospective study was undertaken of 10 patients with leukoplakic commissural lesions, who visited the Department of Oral Surgery in the Teaching Hospital of the Free University, Amsterdam in the period between 1973-1986. The clinical and histopathological findings are presented. Although a carcinoma in this particular region is rather rare, alertness remains necessary as one patient with the clinical appearance typical of leukoplakia, showed on biopsy the presence of a squamous cell carcinoma at this first visit. In another two patients the areas of leukoplakic change were shown histologically to be based on verrucous carcinoma. In one patient a squamous cell carcinoma developed after several years, in spite of treatment. In view of the small number of patients under discussion and also the somewhat debatable diagnosis of verrucous carcinoma, we do not feel justified in drawing any firm conclusions from our findings with regard to the malignant potential of leukoplakia of the oral commissures.