This is representative of leukoplakia, a pre-cancerous lesion of squamous cells. In order for it to spread to distant sites, it must first invade through the basement membrane/submucosa. Could be confused with oral hairy leukoplakia (which also is a white patch that classically arises on the lateral tongue). However, oral hairy leukoplakia is not pre-cancerous and is often associated with EBV infections or people that are severely immunocompromised.
submitted by โnwinkelmann(366)
Per pathologyonlines.com
Leukoplakia = risk factors include male gender, 40-70 years old, smoking, White patch or plaque, 5 mm or more, on oral mucous membranes that cannot be removed by scraping, not due to another disease entity such as lichen planus or candidiasis and not reversed by removal of irritants and lesion must be considered precancerous until proven otherwise. Premalignant lesion transformation would lead to invasion of the submucosa.
Micro = Varies histologically from acanthosis, hyperkeratosis, dysplasia or carcinoma in situ (associated with lymphocytes and macrophages). This article explains it much better and has pictures: https://emedicine.medscape.com/article/1840467-overview#a6. Based on this article and the pictures, I'd say the histo slide in the question is at least moderate squamous dysplasia.
Hairy Leukoplakia = White, confluent patches of fluffy (hairy) mucosa, bilateral, along lateral tongue, and associated with HIV+ patients (AIDS may appear within 2 - 3 years) but actually due to EBV infection
Histo = Hyperkeratotic oral mucosa due to piling of keratotic squamous epithelium, Cowdry type A intranuclear inclusions, Balloon cells with margination of chromatin (nuclear beading); EBV present in clear cells of spinous layer, variable koilocytosis, superimposed Candida infection, without inflammatory response.
From pictures (and this video: https://youtu.be/Shx61qKuIv8 timestamp 1:22), hairy leukoplakia has a lightly stained band of cells "ballon cells" in the stratum spinosum which is where the EBV lives. It looks much different than the histo slide shown in the question.