The role of the Oral Pathologist

If you want to be an oral pathologist, then you have to know what normal tissues look like. And then, you have to be able to identify what abnormal tissues look like. So when you get a biopsy from the lab, it’s on a slide like this. And this is what it would look like under the microscope. But normal tissue actually doesn’t have any colour to it, so this has been stained with special dye called hematoxylin and eosin to give it this nice pink and blue colour. So on this side, this is the lining of the mouth. And it’s called oral mucosa, and it’s got two parts to it.

It’s got the epithelium, which is a bit like your skin, but it lines the surface. And then underneath, it’s got the connective tissues which has all the blood vessels and produce all the nutrients and oxygen that your mucosa needs. So this side is completely normal, with a nice thick epithelial layer and connective tissue underneath. This side actually shows you what diseased mucosa looks like, and this disease is called lichen planus. And it’s a disease that affects the cheeks in particular, and it’s characterised by white patches, instead of a nice pink mucosa. So there are quite important differences here. The first thing I think you might be able to see is that the epithelium is thinner than normal.

So if you compare this to that, it’s much thinner. And that’s called atrophic. It’s atrophic epithelium. The second thing that you might notice is there’s a nice pink player on the top here, whereas there isn’t a pink layer on here. And that’s because the epithelium on this side has produced a layer of keratin. And it doesn’t normally have keratin in the oral mucosa. The third thing is that it’s got these pointy little processes, whereas these don’t have so pointy processes as well. So that’s another difference. And the reason that that’s happened is because these cells, these blue dots here, these are inflammatory cells. And these inflammatory cells are actually destroying the epithelium and making it all pointy.

So these are a special sort of inflammatory cell. They’re called leukocytes, they’re white blood cells. And these ones are lymphocytes, and they actually destroy the epithelium. Now, why they do that, we don’t really understand. But we do know that they do it.