What is Hepatobiliary Adenocarcinoma?
Cancer is caused by a mutation in the DNA, which alters normal cell activity and results in uncontrolled cell growth. This abnormal growth results in neoplasias and tumors that have no functional purpose, and affect the tissues or organs they grow from. In the case of hepatobiliary tumors, the liver, gallbladder, and bile duct functions are affected. Tumors that grow on these areas can cause tissue and organ enlargement, and a subsequent leak of fluids in the abdominal cavity. Often, the disease remains unnoticed due to a lack of symptoms, until it is too late, and becomes fatal.
Hepatobiliary adenocarcinoma is a term used to refer to cancer that affects the liver, gallbladder, and bile ducts. This type of cancer can affect both wild species and companion birds, commonly psittacines and budgerigars. Cancer affecting only the bile duct is called cholangiocarcinoma, and generally affects macaws, conures, and parrots.
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Symptoms of Hepatobiliary Adenocarcinoma in Birds
Often unnoticed in early stages, hepatobiliary adenocarcinoma can progress until the abdomen becomes distended from displaced fluid or enlarged organs. While there often aren’t any other signs that your bird is sick until the disease is in its final stages, you may see other symptoms common to cancer. Signs include:
- Abdominal swelling
- Noticeable internal lump
- Loss of appetite
- Weight loss
- Difficulty breathing
- Loss of body movement control
Causes of Hepatobiliary Adenocarcinoma in Birds
Mutations to the DNA can alter the normal functions of cells. Cancer occurs when these alterations result in abnormal and uncontrollable cell growth that amass into tumors on various organs and tissues. These tumors can grow so large that they interfere with organ function. While researchers and doctors are struggling to understand just how these mutations come about, they do attribute certain influences that may play a role. Specifically, in the case of hepatobiliary adenocarcinoma, certain toxins and infections have been identified that seem to be directly linked. These include:
- Herpesvirus infection
- Trematode infection
- Hormonal disorders
Other possible factors can include:
- Chemical exposure
- Exposure to radiation or sunlight
- Other viral infections
- Genetic disposition
- Exposure to carcinogens, such as second hand smoke
Diagnosis of Hepatobiliary Adenocarcinoma in Birds
Your veterinarian will begin to diagnose your bird with a physical exam. Be sure to tell your veterinarian about the history of symptoms, specifically any masses and their subsequent changes. You should also include any known exposure to birds infected with viruses or parasites. After palpating the area of the mass, your veterinarian will get a better picture of the possible problem, but a definitive diagnosis cannot be made without further testing.
Blood tests, including a CBC and plasma analysis, are performed, as well as a urinalysis. A PCR test may be performed whether or not a virus is suspected, which can detect the presence of the herpesvirus.
Imaging techniques are then used to reveal lesions, tumors, or alterations on the liver, gallbladder, or bile ducts, and can also show the presence of fluid that has leaked into the abdominal cavity. They can also show if the tumors have spread to nearby tissues or organs. Electrocardiography may also be used to gather further details about your bird’s condition.
A cancerous tumor cannot be definitely diagnosed without the testing of a sample of the abnormal tissue. This tissue can be obtained through an endoscopy, laparoscopy, fine-needle aspirate, or from a biopsy which removes part or all of the mass. The tissue is then tested through a microscopic cytological exam, and possibly with staining tests and bacterial cultures.
Treatment of Hepatobiliary Adenocarcinoma in Birds
Treatment of hepatobiliary adenocarcinoma is primarily through removal of the tumor. A surgical excision can be successful in cases of a solitary tumor, or if the tumors are relegated to only one lobe of the liver, in which case that portion of the organ can be removed. Multiple tumors, and tumors that have spread to nearby tissues and organs, can make removal much more difficult, and may not be attempted.
Removal of the tumors is often combined with other treatments. These therapies are also employed when tumor removal is too dangerous, or the tumors are too numerous. Chemotherapy that involves drugs such as carboplatin and cisplatin is often employed, along with radiation and immunotherapy, which helps to stimulate the immune system. Your veterinarian will discuss the side effects that come with chemotherapy and radiation, and will determine with you if your bird’s condition can withstand those effects in order to benefit from them.
Recovery of Hepatobiliary Adenocarcinoma in Birds
The recovery from hepatobiliary adenocarcinoma is variable, and depends on the number of tumors, the size of tumors, the timeframe of cancer growth and treatment, and your particular bird’s species and general health. Solitary tumors can be removed with successful results, and may prove to be curative. However, they may return in time. Multiple tumors, or tumors that have spread to other organs or tissues may be more difficult to treat, or even impossible to remove. This type of cancer can be fatal. Your veterinarian will talk with you about your bird’s chances of recovery based on his specific condition.