Neoplasms and Oncology: Tumors, Masses and Growths

A neoplasm is a new, abnormal growth of tissue which develops as a result of rapid cellular growth. It may be benign or malignant, and it has no physiological function. Budgerigars tend to develop neoplasms as they age at a higher rate than other psittacines. Neurological signs, such as paralysis or paresis (partial paralysis) of the legs, may be evident, and the bird may not be able to maintain its normal position on the perch. Often these growths arise from the liver, kidney, and gonads.^34,58

Cockatiels and cockatoos tend to form pulmonary carcinomas as they age. Clinical signs depend on where the tumor is found and how large it has become. It is not known what causes these neoplasms. Unfortunately, it doesn’t have a good prognosis. ^34,58

Age influences the development of tumors in avian tissue due to “an increase in genetic damage from environmental agents and errors in gene repair." ⁵⁴ The following tumors are often seen in geriatric patients:

11.1 Lipomas

Lipomas are non-malignant, fatty tumors that are most often seen in budgerigars, but Amazons, cockatiels, and other species develop them as well. They are associated with excessive body fat and are usually located on the keel or in the sternopubic (lower abdominal) area.³⁸

Obesity, advanced age, and high-energy diets contribute to lipomas and liposarcomas, according to K. Latimer. In psittacines of any age, xanthomas and liposarcomas may become life-threatening, but they are more quickly fatal in older birds. "Abdominal hernias often develop, and when these are combined with the extensive mass of the lipoma, the have difficulty in evacuating the cloaca, which leads to abrasion, hemorrhage, and infection." ³⁴ Treatment involves weight loss, improving the environment so that the bird does not traumatize the area, and possibly surgery if all else fails. Complications for the older bird may include hepatic lipidosis (fatty liver disease), decreased liver function, and cardiovascular disease. Any surgery should be as non-invasive and as short a duration as possible.³⁴
 

11.2 Air Sac Carcinomas

Air sac carcinomas are rare growths, and it is often difficult to identify the air sac as the tissue in which they originate. They usually occur in older, larger psittacines, such as cockatoos, African greys, macaws, and Amazons. The birds are often brought in initially with cystic masses or bony lesions on the humerus or upper wing bone. ⁵⁴

11.3 Hemangiomas

Hemangiomas are non-cancerous tumors of the vascular endothelium (a single layer of thin cells that lines the inside surface of blood vessels). They are most often found in budgerigars and are usually seen in the skin of the feet, inguinal region, wing, cloaca, spleen, and the side of the neck. Most birds will develop these when they are around ten years of age.⁵⁴
 

11.4 Hemangiosarcomas

Hemangiosarcoma is the cancerous form of the hemangioma. They usually appear on the beak, wings, feet, legs, and cloaca, and are most often seen in cockatiels. But chickens, swans, Amazons, lovebirds, African greys, pionus, budgies/parakeets, canaries, and finches also develop them. The skin tumors appear inflamed and necrotic. They occur at the same rate in both sexes and around the same age as the hemangiomas.⁵⁴

11.5 Hemangiolipomas

Hemangiolipomas, benign tumors of fatty tissue and blood vessels, are not often seen. They are found in the subcutaneous tissue on the body or limbs. In J. Samour’s practice, these have been found on a budgie, a yellow-collared macaw, a cockatiel, a lovebird, an Amazon, and a canary. All of these birds were over 9 years of age.⁵⁴
 

11.6 Hematomas

A hematoma is a collection of blood outside the blood vessel. Causes of their formation include trauma, brain injury, diseases, and infections. Hematomas form when the blood does not clot properly as a result of Vitamin K deficiency. Senior birds may lose their balance and suffer falls or impacts which result in hematomas. Also, as birds age, their skin becomes more fragile. To see the complete series of images dealing with this bird’s surgery, click on the picture to follow the link (image courtesy Peter Wilson, Currumbin Valley Birds, Reptiles, and Exotics Vets; used with permission).
 

11.7 Neoplasias in specific species

In this table you will find a list of the most common types of neoplasias found in the tissues of various species. The most common tumor of captive parrots overall is the lipoma.^21,54Any term that includes the words, “carcinoma” or “sarcoma” refers to cancerous tumors.

Types of Neoplasias

The following information is in CB Greenacre’s paper, “Birds of a Certain Age.” ²⁰

• Over 90% of budgerigars over five years of age will eventually develop leg lameness associated with a renal tumor (usually renal adenocarcinoma) pressing on the sciatic nerve. This is the highest tumor rate of any animal. There is no surgical treatment for this type of tumor.
• Male budgies over five years of age can develop Sertoli-cell tumors or seminomas that secrete estrogen and cause the male’s blue cere to turn brown and produce extra tissue. This is called "brown hypertrophy of the cere." It can be moistened with warm compresses and peeled away. There is no surgical treatment for this condition.
• Cockatoos and Amazon parrots tend to develop adenocarcinomas more often than any other species. Respiratory adenocarcinomas can be found in the wing, axillary, or lung areas of the birds. The lining of the pneumatic humerus can also develop an adenocarcinoma. In Amazons, bile duct carcinoma is found in the liver, especially if the bird also has papillomatous masses in the cloaca due to psittacine herpesvirus. Surgical removal with wing amputation is the usual treatment method.
• Squamous-cell carcinoma (SCC) is most often seen in Amazons, macaws, and African greys. It is usually found in the mouth or beak area of the Amazons and macaws, whereas the uropygial gland is the disease site most frequently seen in African grey parrots. They may occur anywhere on the body, but are usually found in the oral cavity, the sinuses, on the distal wing, the feet, and the uropygial gland. They tend to be highly aggressive and invasive, and complete excision is usually not possible. Experimental treatment with radiation therapy had being done with some success; however, the tumors are very resistant to this treatment, and long-term control is not generally achieved. Distant metastasis rarely occurs. SCC seems to occur with greater frequency in geriatric birds. The carcinomas create constant necrosis, and the therapies often make it worse, providing a breeding ground for bacteria, yeast, and fungal spores. Throughout any treatment, antimicrobial therapy is advised to avoid septicemia.
• Melanomas are not often seen in birds. They are a type of tumor which spreads throughout the body. These malignant tumors are usually found on the beak, in the liver, on the skin of the face (of birds whose faces are featherless, such as macaws), and in the oral cavity of psittacines. They are known to metastasize to the cardiac muscle, kidneys, brain, and the sinuses.
• Fibrosarcomas can be found anywhere on the body, but are usually seen on the face, in the oral cavity, in the long bones, or in the abdominal cavity. "They are locally invasive and will recur if enough tissue isn’t taken during surgical excision." The use of radiation therapy is known to control these growths for a long time. Since they do not metastasize well, radiation and/or chemotherapy have been successful with some patients. (These therapies are no longer use since the patients rarely survive them.)
• Internal carcinomas, such as ovarian neoplasias; renal carcinomas; hepatic adenocarcinomas; bile duct, hepatic and pancreatic adenocarcinomas; and carcinomas of the spleen and GI tract have been reported in older birds. "Once as much as possible of the tumors has been removed, and the type of tumor confirmed by histopathology, drug therapy is usually initiated." ²⁰

Birds tend to have a higher tolerance for some drug therapies than mammals. (R Dahlhausen, personal communication)
 

11.9 Growths and Tumors of the Reproductive System

11.9.1 Tumors of the Female Reproductive Tract

Senior female birds suffer from condition and tumors of the vent, cloaca, uterus or shell gland, and ovaries. Birds with a long history of egg-laying, egg-binding, and insufficient calcium intake to support these processes will often develop growths and tumors as they age.
 

11.9.2 Tumors of the Male Reproductive Tract

11.9.2.1 Sertoli-cell tumors

Sertoli-cell tumors appear yellow-red and cause enlargement of the testis. The clinical signs are anorexia, lethargy, and dyspnea. They are firm, grayish-white neoplasms (new growths), and the signs are anorexia, dyspnea, cardiac changes, and in budgies, brown hypertrophy of the cere. The average age when diagnosed is 10 years. ³⁴
 

11.9.2.2 Brown Hypertrophy of the Cere
 

11.10 Tumors of the Uropygial Gland

The uropygial gland has two lobes, and it is located near the base of the tail on the dorsal (top) side of the body. This gland secretes a fatty, pasty, oily, cream-colored sebaceous substance called "sebum." It is thick in appearance and has a characteristic light, musky smell. The oil is spread on the plumage by the birds during preening to provide waterproofing. The sebum contains the precursors for Vitamin D, and those are converted to Vitamin D when the sebum is exposed to sunlight or artificial UV light. The sebum, now containing the Vitamin D, is then ingested by the bird as it preens. This is the means by which birds absorb Vitamin D. Vitamin supplementation is needed for birds who do not receive sunlight or UV light, or do not have a preen gland.⁵⁵

The secretion is carried by a number of ducts to an external papilla, or nipple, covered by a tuft of down feathers forming what is commonly known as the "wick." One of the most common disorders affecting the uropygial gland is impaction. The gland becomes enlarged, and the wick dries up. Sometimes there is an obstruction with a hardened secretion known as a "lith," which acts as a plug. Applying warm-water compresses to the area and gently massaging it and then expressing the sebum from the gland usually resolves the obstruction.⁵⁵ Sometimes the gland needs the care of an avian veterinarian.⁵⁵
 

When the bird is at the practitioner’s office, its uropygial gland should be examined for evidence of abnormalities, such as enlargement, inflammation, impaction, abscessation, and neoplasia. Any of these may lead to self-mutilation or trauma by the bird.⁵⁵

Some species of birds possess a uropygial gland, and others do not. Most psittacines have this gland.
 

11.10.1 Species which do or do not possess a uropygial gland: ⁵

Uropygial Gland Absent

• Argus pheasant
• Citron cockatoo
• Woodpecker
• Cormorant
• Double-headed Amazon
• Yellow-Fronted Amazon
• Cassowary
• Green-winged macaw
• African Grey
• Sun Conure
• Tailless Domestic Fowl
• Umbrella Cockatoo
• Rock Dove (pigeon)
• White carneau and rumples pigeon
• Blue and Gold macaw

Uropygial Gland Present

• African Grey
• Eclectus
• Goffin Cockatoo
• Budgerigar
• Gold-capped conure
• Cockatiel
• Indian Ringneck
• Grey-cheeked parakeet
• Muluccan cockatoo
• Hyacinth Macaw
• Red-masked conure
• Red-cheeked conure
• Rose-breasted cockatoo
• Emu and ostrich
• Severe macaw

Uropygial gland tumors can be either adenomas or carcinomas, and it is difficult to tell the difference visually. Both will appear as swellings and may be inflamed. "Adenomas are usually well circumscribed and encapsulated, whereas carcinomas appear to be less defined and will infiltrate the surrounding tissue." ⁵⁷
 

11.11 Xanthomas

Xanthomas are growths that occur usually on the wing but can spread to the body and occur internally, in or around the heart. They are friable, yellow-colored, fatty-appearing masses that may be found anywhere on the body, but the most commonly seen places are on the distal wing and in the keel area. They are found mostly on older psittacines.⁴⁶ They are not true neoplasms since they are caused by excess fat and cholesterol in the diet, usually from all-seed diets and lack of exercise. As the fat and cholesterol build up, the xanthoma continues to grow until it is so huge that surgical excision of the mass may be required, and sometimes amputation is necessary.⁴⁶ If attended to early in the disease process, the xanthoma may be corrected by dietary changes, exercise, and a non-surgical treatment protocol which the author of this paper has developed.⁴⁶

The disease often causes inflammation of underlying tissues. When located at the wing tip, the mass may cause the wing to droop, resulting in trauma to the mass, inability to fly, and an altered gait. The diet should be changed to one that is low in protein and fat.⁴⁶ Serum cholesterol levels should be closely monitored; they are usually elevated in birds with xanthomatosis and should be medically reduced to a normal level prior to surgery.⁶

The average age of affected birds is 10 years (range 3-30 years), and they are found most often on cockatiels and budgies. They may also be found on lovebirds, Amazons, macaws, cockatoos, and African greys. According to Reavill and Dorenstien, "They are masses of foamy macrophages, giant cells, and cholesterol deposits that produce thickened, dimpled skin with yellow-orange coloration. They may occur in internal organs." ⁵⁴ The aortic arch tends to hold onto the cholesterol. They are very vascular, and “may affect the brain where it appears in association with blood vessels.” ⁵ Because they are so vascular, any surgery performed must be done very carefully as they will bleed easily. Cold-laser therapy is being used on them with some success.⁵⁴

There is evidence that ginseng reduces the fat and cholesterol deposits within the xanthomas and within and around the heart. The author’s cockatiel responded favorably to this herbal supplement, recommended by Bob Dahlhausen.