Todayโs path rounds are on ๐๐ก๐จ๐ฅ๐๐ฌ๐ญ๐๐๐ญ๐จ๐ฆ๐๐ฌ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ก๐จ๐ฅ๐๐ฌ๐ญ๐๐๐ญ๐จ๐ฆ๐๐ฌ are collections of ๐๐ก๐จ๐ฅ๐๐ฌ๐ญ๐๐ซ๐จ๐ฅ that form large, tumour-like nodules. We most commonly see these in the brain!
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
This condition is almost exclusive to old horses, with 15-20% of old horses having a cholesteatoma. Wild!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
The exact cause of cholesteatomas is unknown, however it is thought to be related to repeated ๐๐จ๐ง๐ ๐๐ฌ๐ญ๐ข๐จ๐ง (blood pooling) in the ๐๐ก๐จ๐ซ๐จ๐ข๐ ๐ฉ๐ฅ๐๐ฑ๐ฎ๐ฌ, the collection of cells and vessels that produces the ๐๐๐ซ๐๐๐ซ๐จ๐ฌ๐ฉ๐ข๐ง๐๐ฅ ๐๐ฅ๐ฎ๐ข๐ (CSF) that protects the brain and spinal cord from impact. When there is congestion of the choroid plexus, the tissue is infiltrated by ๐ฆ๐๐๐ซ๐จ๐ฉ๐ก๐๐ ๐๐ฌ (the bodyโs major clean up cell) that contain fat and cholesterol. The macrophages leave this cholesterol behind in the tissue, leading to a cholesteatoma over time.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
As you might imagine, having a big blob of fat in your brain is not ideal! Cholesteatomas are most commonly found in the ๐ฏ๐๐ง๐ญ๐ซ๐ข๐๐ฅ๐๐ฌ of the brain, which are large chambers containing cerebrospinal fluid. Over time, the increasing size of the cholesteatoma can block proper CSF flow, causing ๐ก๐ฒ๐๐ซ๐จ๐๐๐ฉ๐ก๐๐ฅ๐ฎ๐ฌ. In this condition, the ventricles become larger and larger due to fluid accumulation, which compresses the brain tissue around the ventricle. Over time, these animals may develop ๐ง๐๐ฎ๐ซ๐จ๐ฅ๐จ๐ ๐ข๐ ๐ฌ๐ข๐ ๐ง๐ฌ like ๐๐ญ๐๐ฑ๐ข๐ (wobbly gait), loss of balance or even seizures.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Unfortunately, horses are rather difficult to get a brain MRI on! Additionally, there are no treatment options available even if a cholesteatoma is suspected. Therefore, these animals are often euthanized, and diagnosis is made at necropsy.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-4) Cholesteatomas in the brain! Itโs not hard to imagine how these fat blobs would affect brain function.
5) What cholesteatomas look like under the microscope! Our routine staining procedure actually removes fat, so all we are left with are these shard-like, blank areas called ๐๐ก๐จ๐ฅ๐๐ฌ๐ญ๐๐ซ๐จ๐ฅ ๐๐ฅ๐๐๐ญ๐ฌ. Neat!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 1. Sixth Edition.
Photos 1-5 ยฉ Noahโs Arkive contributors Render, Saunders, Rooney, Williams, Ward licensed under CC BY-SA 4.0.
