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.
- Kristine said Hi Cynthia – Yes!! I totally agree. I remember learning that if you see any secondary granulat...
- Cynthia said I’m going to have agree with the granules being the most important. I’m also MT and I...
- AG said Thanks Kristine, very helpful!
- Frank MD said Succinctly explained. Excellent! Thank you so much!!
- kartik said Thanks,i am learner,when i think hypothtically,i think i may find confusing beetween promyelocyte an...
- Carol said Thanks…. Well explained
- Ulyses Yakovlevich said This looks like an awesome tool for future Pathologists to learn from :).
- Chief said Amazing explanation. No other website teaches this interesting and important medical lesson. Not eve...
- Dr.Kisor Kumar Pal said Very helpful and practical discussion.I learned a lot.
- Cheri said Thank you ! I’m a traveler in Pathology/Histology
- Dr. Syed Mahbub Baksh said During my residency years, I have read only two books: Robbins Pathology and Henry’s Clinical...
- Theresa said Thanks for breaking this down in a simple way to understand it. Well done.