How to differentiate acute vs. chronic inflammation in sections
Posted Feb 06 2012 7:11am
One thing that’s hard to get the hang of in pathology is the difference in appearance between chronic and acute inflammation in tissue sections. It’s pretty easy to tell a neutrophil from a lymphocyte in blood smears – but it’s a different story in tissue sections. Someone will show a low-power image in lecture and say it’s obviously chronic inflammation – but how are you supposed to be able to recognize that?
The most helpful idea to keep in mind, I think, is how “busy” the collection of cells looks. If you think about the morphologic differences between neutrophils and lymphocytes, the most obvious one is the nucleus. The nucleus of a neutrophil has several lobes (which is why it’s sometimes called a polymorphonuclear cell), but the nucleus of a lymphocyte is a single, large, dark circle.
When you look at a bunch of neutrophils in section, you’ll see a lot of cells with multi-part nuclei that look like little Mickey Mouse ears. Check out the upper photo. Acute inflammation looks messy, or busy, like a bunch of dots of all different sizes.
When you look at a bunch of lymphocytes in section, though, you’ll see a bunch of similarly-sized, uniform, dark blue dots. Check out the lower photo. Chronic inflammation looks more uniform, like somebody had a rubber stamp of a little purple dot, and they just stamped it over and over on the slide.
One thing that’s hard to get the hang of in pathology is the difference in appearance between chronic and acute inflammation in tissue sections. It’s pretty easy to tell a neutrophil from a lymphocyte in blood smears – but it’s a different story in tissue sections. Someone will show a low-power image in lecture and say it’s obviously chronic inflammation – but how are you supposed to be able to recognize that?
The most helpful idea to keep in mind, I think, is how “busy” the collection of cells looks. If you think about the morphologic differences between neutrophils and lymphocytes, the most obvious one is the nucleus. The nucleus of a neutrophil has several lobes (which is why it’s sometimes called a polymorphonuclear cell), but the nucleus of a lymphocyte is a single, large, dark circle.
When you look at a bunch of neutrophils in section, you’ll see a lot of cells with multi-part nuclei that look like little Mickey Mouse ears. Check out the upper photo. Acute inflammation looks messy, or busy, like a bunch of dots of all different sizes.
When you look at a bunch of lymphocytes in section, though, you’ll see a bunch of similarly-sized, uniform, dark blue dots. Check out the lower photo. Chronic inflammation looks more uniform, like somebody had a rubber stamp of a little purple dot, and they just stamped it over and over on the slide.
I kinda want to clean up the top photo.