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. Erythroplakia 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, erythroplakia appears red when viewed in a clinical setting. Treatment Treatment involves biopsy of the lesion to identify extent of dysplasia. Complete excision of the lesion is sometimes advised depending on the histopathology found in the biopsy. Even in these cases, recurrence of the erythroplakia is common and, thus, long-term monitoring is needed. History In 1911, French dermatologist Louis Queyrat described a sharply defined, bright red, glistening velvety precancerous lesion of the glans penis. He coined the term "erythroplasie" to designate red plaques as an analogy to "leucoplasie", which designated white patches. Since "leucoplasie" was the equivalent of the English leukoplakia (coined in 1861), the term became erythroplakia in English. Similarly, the term leukoplakia was originally coined to describe white lesions of the urinary tract, and in 1877 was first applied to white patches in the mouth. It is unclear when the term erythroplakia was first adapted to describe red lesions in the mouth. Etymology The word erythroplakia means "red patch", and is derived from the Greek words ερυθρος - "red" and πλάξ - "plate" The World Health Organization defines oral erythroplakia as follows: References External links Conditions of the mucous membranes Oral mucosal pathology