What are Musculoskeletal Neoplasms?

Common types of neoplasms that are found in these systems can include chondroma, chondrosarcoma, hemangioma, leiomyosarcoma, and osteosarcoma. Avian neoplasms are typically removed by surgery as soon as possible, particularly if they are showing any evidence of growth or if they are prone to malignancy. Any new or unusual growths that are found on your bird should be evaluated by a veterinary professional.

There are several varieties of neoplasm that can involve the musculoskeletal system, both benign and malignant.

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Symptoms of Musculoskeletal Neoplasms in Birds

The symptoms of neoplasms found in the musculoskeletal system can vary depending on where in that system they are located, the size of the neoplasm, and whether or not the original tumor has metastasized. Commonly seen symptoms may include:

  • Blood in droppings
  • Exercise intolerance
  • Labored breathing
  • Necrosis or ulceration of the skin over neoplasm
  • Palpable lumps or bumps
  • Rapid breathing
  • Regurgitation
  • Swelling 
  • Vomiting
  • Weight loss 

Types 

Chondroma

Birds in the Anseriformes family, which includes ducks, geese, and swans, are overrepresented in this category. They often occur on the foot, the cranium, and the proximal humerus.

Chondrosarcoma

Cases of chondrosarcoma are not unheard of in avians, but they are very rare. Although chondrosarcomas are commonly metastatic when they develop in mammals, they do not often appear to become metastatic in birds. 

Hemangioma

This type of tumor is made up of tiny blood vessels and can bleed profusely if it is popped or cut. 

Leiomyosarcoma

The most common neoplasm found in the muscles of both captive and free-ranging birds and can occur in any smooth muscle in the avian body. Metastasis is an infrequent occurrence that tends to attack the liver, spleen, thoracic cavity, and bone marrow. 

Osteosarcoma

Osteosarcomas in birds tend to appear on the long bones such as the radius, humerus, tibiotarsus, tarsometatarsus, and femur. They can also originate on the ribs, phalanges, cranium, orbit, and coccyx, although these placements are less common. These tumors may aggressively metastasize to other areas of the body, including the lungs, liver, and kidneys.

Causes of Musculoskeletal Neoplasms in Birds

The causes of neoplasms in avians are as mysterious as tumors in other animals, including humans. Although we are not privy to all of the conditions that can cause tumors to grow, we do know some of the circumstances that can predispose an animal to developing them. 

Environmental Factors

Exposure to carcinogens such as secondhand smoke, aerosolized chemicals, or chemical finishes on cages and perches may contribute to the formation of avian neoplasms. 

Genetic

The development of any cancer has a genetic component, and certain families or species of birds are more prone to some types of cancer. In general, neoplasms are most commonly reported in birds of the Psittaciform order, known more commonly as parrots, while it is only sporadically reported in the perching songbirds of the Passerform order. 

Viral infections

There is a link between tumors in birds and viruses, particularly herpesviruses and retroviruses. 

Diagnosis of Musculoskeletal Neoplasms in Birds

The visit to the avian veterinarian will most likely start out with a general physical examination. The bird will be weighed and measured and then examined from head to toe as well as checked for the proper functioning of the eyes, ears, and cere, the animal will have its skeletal system and musculature evaluated. Many musculoskeletal neoplasms can be felt manually and may be found and given a preliminary assessment during this procedure. Standard blood tests will be valuable in gauging the effects of any tumors that are present, for instance, tumors that involve the skeletal system may trigger an increase of calcium or phosphorus in the circulatory system as the bone is broken down. 

If the tumor is malignant, these tests may also help to indicate if there is any impairment of the liver or kidneys by determining the levels of enzymes circulating in the blood. Samples will also be taken of any lesions that are found, using a small gauge needle. The samples will be submitted for biopsy, which will establish whether the growth is malignant or benign. Both computed tomography (CT) scans and ultrasound imaging are commonly used to get a clearer picture of the tumor or tumors present, and scintigraphy is occasionally employed to better detect early tumors that affect the bones. These procedures are crucial in determining the next steps as the size and location of the growth will be vital in determining the best treatment plan for the specific animal.

Treatment of Musculoskeletal Neoplasms in Birds

The treatment plan for birds that are afflicted with musculoskeletal neoplasms will be dependent on the type of neoplasm that has developed, the placement of the growth, and whether or not the tumor has metastasized or has a high probability of metastasizing. Surgical removal of the neoplasm is almost always indicated with the exception of static, benign tumors that do not interfere with the patient’s quality of life, however, the amount of surrounding tissue that needs to be removed will vary depending on the characteristics of the neoplasm. In some cases, surgical excision is implausible and alternate forms of therapy such as external beam radiation, cryotherapy, or photodynamic therapy may be considered instead.

Some types of neoplasm may necessitate additional treatments to eradicate the growth and keep it from spreading. Avians have a higher tolerance for chemotherapeutic medications than most mammals, unfortunately, the neoplasms that form in the musculoskeletal system of birds are also more resistant to radiation and chemotherapy. Due to the rapidly changing landscape of cancer treatments in birds, a veterinary oncologist with avian experience should be consulted when developing the treatment plan.

Recovery of Musculoskeletal Neoplasms in Birds

After surgery, birds are generally placed in a hospital environment, where the most beneficial oxygen levels, temperature, and humidity levels can be rigorously monitored until the patient has fully awakened. Medications to manage the pain are frequently administered by injection while the bird is still sedated to reduce the stress levels on awakening, and if the hospitalized bird is a companion animal, healing is often sped up by time spent with their favorite humans, so visitation is recommended if it is allowed during a prolonged hospital stay.

Some birds with sutures may require a bandage or collar to prevent them from picking at the area, and if the sutures are non-dissolving, another appointment will be needed to have them removed in five to ten days. It is crucial to follow your veterinarian’s instructions regarding medications and to ensure that the animal gets plenty of rest during its recovery period.