Uterine Adenocarcinoma in Rabbits
Uterine adenocarcinoma, a gland-like, malignant type of tumor that arises from the secretory tissue that lines the inner cavity of the uterus, is one of the most common forms of cancer in rabbits, occurring in up to 60 percent of female rabbits over three years old. These malignant uterine tumors usually arise from the endometrial lining of the uterus, or from the inside layers of the uterus.
Often uterine cancer forms after a rabbit has already developed some other reproductive problem in its uterus, including endometriosis, a painful condition involving tissue overgrowth in the uterus and reproductive organs. Age seems to be the most important risk factor for this condition. Tumors can also be found in concurrence with other conditions, including bulging veins in the endometrial lining, a condition also referred to as venous aneurysms.
Symptoms and Types
The signs and symptoms of uterine adenocarcinoma vary from rabbit to rabbit, although generally any female rabbit over 3-4 years of age is most at risk. The presence of blood in the urine is one of the most common findings in female rabbits; other typicaly symptoms include:
- Vaginal discharge stained with blood
- Cysts in the mammary glands, and cloudy fluid that may come from the mammary glands
- Behavioral changes, including aggressiveness
- Lethargy, inability to eat, and pale mucous membranes (typically occur in later stages of illness)
- Abdominal masses (typically occur in later stages of illness))
- Mammary growths
Any female rabbit that is still capable of reproducing is at risk for uterine cancer.
The diagnosis usually begins with the exclusion of other causes for the symptoms, including the most obvious cause for a mass in the abdomen: pregnancy. Benign or non-cancerous uterine tumors can also cause many of the symptoms and signs described above. An overgrowth of cells may be associated with other benign conditions as well; however, the symptoms found here are most often ascribed to adenocarcinoma or cancer, especially in females that are greater than three years of age. Anemia often accompanies this condition in females and is helpful for diagnosing the condition.
Abnormal results from imaging studies, (i.e., X-ray, ultrasound) can also help to diagnose the condition, as can swollen or abnormal lymph node findings, which are suggestive of the spread of the disease. A definitive diagnosis can be made on the results of a biopsy of the uterine tissue.