Todayโs path rounds are on ๐ก๐ข๐ฌ๐ญ๐ข๐จ๐๐ฒ๐ญ๐จ๐ฆ๐๐ฌ! This was a request 
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ข๐ฌ๐ญ๐ข๐จ๐๐ฒ๐ญ๐จ๐ฆ๐๐ฌ are a benign tumour that are derived from skin ๐๐๐ง๐๐ซ๐ข๐ญ๐ข๐ ๐๐๐ฅ๐ฅ๐ฌ, which are cells that pick up weird foreign proteins and show them to the immune system for identification. In the skin, these cells are specifically called ๐๐๐ง๐ ๐๐ซ๐ก๐๐ง๐ฌ ๐๐๐ฅ๐ฅ๐ฌ.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
Technically this tumour can occur in any species, however we most commonly think of it in dogs. Specifically, this tumour often occurs in young dogs, and Boxers and Dachshunds appear to be predisposed.
๐๐ก๐๐ญ ๐๐จ๐๐ฌ ๐ข๐ญ ๐ฅ๐จ๐จ๐ค ๐ฅ๐ข๐ค๐?
These tumours look like a raised, red nodule on the skin, that kind of look like a button. They are most commonly found on the head and ears. These nodules often have no hair over them, and can grow quite rapidly, seemingly overnight! Interestingly, these tumours often ๐ฌ๐ฉ๐จ๐ง๐ญ๐๐ง๐๐จ๐ฎ๐ฌ๐ฅ๐ฒ ๐ซ๐๐ ๐ซ๐๐ฌ๐ฌ, meaning they just go away after a while.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Because these tumours spontaneously regress, they often donโt cause any issues for the animal. However, sometimes the tumour can be itchy or bothersome, and they will lick at them incessantly. In these cases, the mass might become ๐ฎ๐ฅ๐๐๐ซ๐๐ญ๐๐ and bleed.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
The best method of diagnosis is a ๐๐ข๐จ๐ฉ๐ฌ๐ฒ (removal of the tumour) for submission to a pathologist, however in the vet clinic they can be diagnosed by ๐๐ข๐ง๐ ๐ง๐๐๐๐ฅ๐ ๐๐ฌ๐ฉ๐ข๐ซ๐๐ญ๐, where a sample of cells is taken using a needle and then examined under the microscope. On an aspirate, you can oval shaped cells with a large amount of ๐๐ฒ๐ญ๐จ๐ฉ๐ฅ๐๐ฌ๐ฆ (cell contents), that kind of look like fried eggs. Neat!
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Typically these are โtreatedโ with ๐๐๐ง๐ข๐ ๐ง ๐ง๐๐ ๐ฅ๐๐๐ญ, otherwise known as doing nothing and watching it for changes. If the tumour spontaneously regresses, great! If not, they can be surgically removed if they are bothering the dog or the owner.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-4) Examples of โbutton tumoursโ diagnosed as histiocytomas!
5-6) Lovely fried egg cells on cytology.
7) An example of what these tumours look like on ๐ก๐ข๐ฌ๐ญ๐จ๐ฉ๐๐ญ๐ก๐จ๐ฅ๐จ๐ ๐ฒ. Basically, the skin is just chocked full of these dendritic cells! Normally this tissue would look very pink under the microscope, but the large number of cells makes it look blue.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 1. Sixth Edition.
Photos 1-7 ยฉ Noahโs Arkive contributors McGavin, French, Eastep, Domingo, Medleau licensed under CC BY-SA 4.0.
