Photodynamic therapy outcome for oral verrucous hyperplasia depends on the clinical appearance, size, color, epithelial dysplasia, and surface keratin thickness of the lesion.

Our previous studies showed that oral verrucous hyperplasia (OVH) lesions can be successfully treated with a topical 5-aminolevulinic acid-mediated photodynamic therapy (topical ALA-PDT) protocol using a 635-nm light-emitting diode light source. In this study, we report the clinical outcomes of 36 OVH lesions treated by this protocol and assess what clinicopathological parameters of OVH lesions could influence PDT treatment outcomes. We found that all the 36 OVH lesions showed complete response (CR) after an average of 3.8 (range, 1-6) treatments of topical ALA-PDT. OVH lesions with an clinical appearance of a mass, with the greatest diameter <1.5 cm, with the pink color, with epithelial dysplasia, or with the surface keratin layer < or =40 microm needed significantly less mean treatment numbers of PDT to achieve a CR than OVH lesions with an outer appearance of a plaque or a combination type of peripheral plaque and central mass (p=0.000), with the greatest diameter > or =1.5 cm (p=0.011), with the white color (p=0.000), without epithelial dysplasia (p=0.043), or with the surface keratin layer > 40 microm(p=0.003), respectively. Multivariate analysis showed that only the clinical appearance of OVH lesions was the independent factor (p=0.0069). We conclude that complete regression of OVH lesions can be achieved by less than seven treatments of topical ALA-PDT once a week. The PDT treatment outcome for OVH depends on the outer appearance, size, color, epithelial dysplasia, and surface keratin thickness of the lesion.