Differential diagnosis of an oral red lesion There are many other conditions that are similar in appearance and must be ruled out before a diagnosis of<unk>  is made (see table). Sometimes, a diagnosis is delayed for up to two weeks in order to see if the lesion spontaneously regresses on its own or if another cause can be found.<unk>  frequently is associated with dysplasia, and is thus a precancerous lesion. Biopsy Microscopically, the tissue exhibits severe epithelial dysplasia, carcinoma-in-situ, or invasive squamous cell carcinoma in 90% of cases. There is an absence of keratin production and a reduced number of epithelial cells. Since the underlying vascular structures are less hidden by tissue,<unk>  appears red when viewed in a clinical setting.
Erythroplakia
Malakoplakia
Microspherophakia
Leukoplakia
Epikeratophakia
Telogen effluvium
Hairy leukoplakia
Aphakia