(Other names: breast blisters, seroma)
Deer with a hydrocyst (right). Although unsightly, hydrocysts rarely cause the deer harm and do not pose a threat to human health.
Description
Often mistaken for cancerous tumors, hydrocysts are large cystlike growths that typically occur in the brisket area of a deer. They are of notable size, often as large as a basketball. Occasionally, the size of the mass may hinder deer movements. This could lead to impaired feeding abilities and could make the deer more susceptible to predators.
Transmission
Hydrocysts are a deer’s body responding to an injury. After an injury, fluids can sometimes accumulate under the skin and form a hydrocyst. This condition is not transmissible from one animal to another.
Clinical Signs
Hydrocysts look like large spherical masses on the brisket area of a deer; however, it is possible to see them on other areas of the body. When a hydrocyst is punctured, the accumulated substance is usually a clear fluid that is sometimes tinted yellow or red.
Wildlife Management Implications
Management of this condition is not necessary because it does not normally harm deer. However, Indiana DNR does track the occurrence of this condition. If you see a deer with hydrocysts, report the animal using our online sick or dead wildlife reporting tool.
Human Health Significance
Although unsightly, hydrocysts present no threat to humans. Meat from an animal with hydrocysts is safe to eat, although it is recommended to avoid eating the meat directly in contact with the cyst.