Todayโs path rounds are on ๐ก๐ฒ๐ฉ๐๐ซ๐ญ๐ซ๐จ๐ฉ๐ก๐ข๐ ๐จ๐ฌ๐ญ๐๐จ๐ฉ๐๐ญ๐ก๐ฒ! This is one of my favourite diseases 
In fact, seeing the skeleton shown in these photos when I was at vet school was one of my big inspirations to go into pathology!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ฒ๐ฉ๐๐ซ๐ญ๐ซ๐จ๐ฉ๐ก๐ข๐ ๐จ๐ฌ๐ญ๐๐จ๐ฉ๐๐ญ๐ก๐ฒ is characterized by ๐ฉ๐๐ซ๐ข๐จ๐ฌ๐ญ๐๐๐ฅ ๐ง๐๐ฐ ๐๐จ๐ง๐ ๐๐จ๐ซ๐ฆ๐๐ญ๐ข๐จ๐ง, meaning proliferation of bone on the outside of existing bones. This proliferation affects the long bones of the limbs primarily.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
This condition can be seen in many different species, but is most commonly reported in dogs.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
These proliferations are associated with chronic inflammatory or cancerous lesions in the thoracic cavity that are ๐ฌ๐ฉ๐๐๐-๐จ๐๐๐ฎ๐ฉ๐ฒ๐ข๐ง๐ . How these space-occupying masses cause bone proliferation in the limbs is unknown! It has been suggested that thoracic lesions may release some type of hormone that that stimulates bone proliferation, or perhaps the lesion impedes on the vessels causing abnormal blood flow to the limbs.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
These lesions are quite painful, but generally the bigger problem for the dog is whatever is going on in the thoracic cavity to cause the boney proliferation. In many cases, these space-occupying lesions are tumours, which is a sad time for the animal.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
The boney proliferation makes the legs look fat, which can be the first clue for the clinician that something is going on. From there, X-rays can show the boney proliferation, and X-rays or ultrasound can demonstrate the thoracic mass, confirming the diagnosis.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Unfortunately there have not been many successful treatments identified. These animals are often euthanized due to the poor prognosis of their thoracic lesion.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-3) X-rays of a dog with hypertrophic osteopathy.
4) An X-ray of the same dogโs thorax showing a very opaque thorax! Normally the thorax is relatively clear.
5-6) The pulmonary mass that caused the hypertrophic osteopathy in this case.
7-8) The skeleton of the same dog after post-mortem. So crazy!!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 1. Sixth Edition.
Photos 1-8 courtesy of University of Calgary Diagnostic Services Unit.
