Todayโs path rounds are on ๐ฌ๐๐ซ๐จ๐ฎ๐ฌ ๐๐ญ๐ซ๐จ๐ฉ๐ก๐ฒ ๐จ๐ ๐๐๐ญ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐๐ซ๐จ๐ฎ๐ฌ ๐๐ญ๐ซ๐จ๐ฉ๐ก๐ฒ ๐จ๐ ๐๐๐ญ is when the fat becomes jelly-like and clear, rather than having its normal fatty yellow appearance.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
Any species can get this!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Serous atrophy of fat is a specific finding in cases of ๐๐๐๐ก๐๐ฑ๐ข๐ (wasting of the body due to severe illness, like cancer) or severe ๐ฆ๐๐ฅ๐ง๐ฎ๐ญ๐ซ๐ข๐ญ๐ข๐จ๐ง. In fact, it is one of the main things a pathologist will look for when trying to determine if an animal starved to death.
As mentioned, the fat becomes rather jelly-like and clear, giving it an almost watery appearance. The best places to look for this change are in the ๐๐จ๐ง๐ ๐ฆ๐๐ซ๐ซ๐จ๐ฐ and around the ๐ก๐๐๐ซ๐ญ. In both locations, the fat becomes jelly-like because that fat store has been entirely used up, as the animal desperately tries to maintain its energy stores. In the bone marrow, all that remains after the fat is gone is ๐ ๐ฅ๐ฒ๐๐จ๐ฌ๐๐ฆ๐ข๐ง๐จ๐ ๐ฅ๐ฒ๐๐๐ง, a form of structural sugar that is translucent and squishy. Poor bone marrow 
In the heart, the fat is often replaced by a protein-rich fluid, giving it a similar appearance.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
This diagnosis is pretty much exclusively made during necropsy, and supports the finding of a starved or cachexic animal. To further support their finding, especially in legal cases, pathologists might take a sample of bone marrow and leave it out to dry in a petri dish. They will weigh the bone marrow daily, until there is no longer a change in weight. This gives them the amount of fat left in that bone marrow sample, after the fluid evaporates. The amount of fat leftover is divided by the initial starting weight of the sample, and that proportion can be used to confirm a diagnosis of starvation. Neat!
๐๐ก๐จ๐ญ๐จ๐ฌ
1) An example of normal bone marrow for you to compare to. Notice how it is somewhat fatty and has a white-ish appearance, and is pretty opaque.
2-6) Examples of serous atrophy of fat in the bone marrow! So gelatinous.
7) An example of serous atrophy of fat around the heart. That yellow, gooey looking stuff was once a fat store for the animal!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 3. Sixth Edition.
Photos 1, 3-7 ยฉ Noahโs Arkive contributor Ramos, Rech, OโToole, Boosinger/Chang, Jennings licensed under CC BY-SA 4.0.
Photo 2 ยฉ University of Calgary Diagnostic Services Unit.
