This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

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Bone cysts are fluid-filled swellings of the bone. They are rare in the dog.

The cause of bone cysts is not known. Single cysts are lined with connective tissue when examined microscopically, whereas multiple cysts are more complex consisting of an inner lining membrane with an eosinophilic layer and a layer of nucleated cells surrounded by oedema and vascular tissue.

Breed Occurence
The Afghan Hound, Doberman Pinscher, German Shepherd Dog, Great Dane, Irish Wolfhound, Saluki and Weimaraner have been reported to be affected with single (monostotic) bone cysts.

The Doberman Pinscher, Golden Retriever and Mastiff-crosses have been reported to be affected with multiple (polyostotic) bone cysts. This condition is thought to be an hereditary disorder in Doberman Pinschers.

The age of animals presented with single cysts is young, ranging from 4.5 months to 2.5 years.

All dogs reported to have developed multiple bone cysts were less than 1 year of age.

During their development phase bone cysts may cause no signs, but the owner my notice swelling of the leg in the region of the cyst. Large cysts can cause lameness particularly if the cyst forms near a joint . Thin walled cysts can fracture causing sudden onset lameness and pain.

Xrays confirm the diagnosis. Cysts appear as black radiolucent swellings in the metaphysis of the long bones (most often the ulna or radius in the foreleg). There is thinning of the walls (cortices) of the bone and in some cases fracture of the wall, leading to an increase in density in the cavity due to haemorrhage.

Following a fracture cysts may heal spontaneously. In other cases they can be surgically opened and scraped with a currette. Some authors put bone grafts into the cavity to promote healing.


Updated October 2013