Canker sores and oral cancer lesions may seem similar but there are ways to tell the difference. A lesion that's red, typically flat, and painful early on is usually a canker sore (aphthous ulcer).

The clinical features, etiology, and treatment of recurrent aphthous ulcers (RAU) are discussed. Aphthous ulcers are among the most common oral lesions in the general population, with a frequency ...