- Mammary Tumors
- Mast Cell Tumors
- Soft-tissue Sarcoma
- Hepatic Carcinoma
- Squamous Cell Carcinoma
- Gastric Cancer
- Brain Tumors
- Malignant Histiocytosis
- Prostate Cancer
- Transitional Cell Carcinoma
The dermal variety appears as dark skin lesions that may be raised and often appear on areas like the abdomen. These are the most curable because they’re easily spotted and have the best chance of being surgically removed. Still, 30% of dogs with dermal Hemangiosarcoma develop metastatic disease, so it’s important to treat the disease immediately.
Hypodermal, or under the skin, hemangiosarcoma can occur anywhere on the body. The tumors may take the form of a soft or a firm mass. 60% of dogs with this version of hemangiosarcoma develop metastatic disease.
As you might surmise, visceral hemangiosarcoma is the most virulent. Its blister-like formations are fragile and can bleed, disrupting normal organ function. The tumors associated with visceral hemangiosarcoma most often form on the spleen, right heart base, or liver, although varieties also appear on the kidney or the bladder. Regardless of where it originates, visceral hemangiosarcoma can spread quickly.
With visceral hemangiosarcoma, often it isn’t evident that the dog is ill until the tumor ruptures and the dog collapses. Other symptoms of can include include loss of appetite, swollen stomach, weight loss, weakness, lethargy or visible skin tumors.
The most common form of canine lymphoma is called Lymphosarcoma, but the information you’ll read here pertains to all forms of lymphoma in dogs. Treatments are essentially the same for all types of dog lymphoma. Lymphoma in dogs is an immune dysfunction disease that results from a failure of the dog’s body to recognize the aberrant cancer cells. Virtually half of all dogs with lymphoma can be put into remission through the use of modern treatment methods.
Signs and Symptoms of Lymphoma. Canine lymphoma patients are typically middle-aged dogs whose owner has discovered one or more lumps. Lymphoma or Lymphosarcoma can occur in the lymph nodes, spleen, liver, and other organs. The first signs are swelling in the neck or a sign found during a normal checkup. There may not be any other signs of illness. He or she may be active, eating normally and even playing as usual. If your dog has lumps in the areas of major joints (neck, shoulders, armpits or knees) have your dog examined ASAP by a veterinarian, even if he or she appears healthy.
Osteosarcoma accounts for 80-90% of malignancies involving bone cancer in dogs. The typical patient is an older dog of a large breed. Osteosarcoma begins on the surface of the bone and progresses inward, disintegrating the bone. There are various forms, but the treatments are similar and this information applies to all varieties of the disease. The promising news is that, with treatment some dogs with osteosarcoma can be put into remission if the disease is discovered early enough.
Signs and Symptoms of Osteosarcoma. The problem is that the usual symptoms, lameness and pain, don’t usually develop until the cancer is advanced. It might at first seem like a case of arthritis or a muscle pull, but any lameness or swelling on your dog’s legs or ribs should be checked out as soon as possible.
Mammary (or breast) tumors are common in female dogs, but rare in male dogs. Surgical removal is recommended for most mammary tumors. Chemotherapy may be required following surgery in some cases. The prognosis is good following surgical resection for most mammary tumors in female dogs, but the prognosis is worse for certain types of tumors in dogs.
Mammary tumors are more common in female dogs that are either not spayed or were spayed after 2 years of age. More than a quarter of unspayed female dogs will develop a mammary tumor during their lifetime. The risk is much lower for spayed female dogs, male dogs. In female dogs, 50% of mammary tumors are benign and 50% are malignant.
Signs and Symptoms. A palpable mass underneath the skin of the abdomen is the most common findings in dogs with mammary tumors. Other signs and symptoms include discharge from a mammary gland, ulceration of the skin over a gland, painful, swollen breasts, loss of appetite, weight loss, and generalized weakness.
Mast cell tumor (MCT) represents a cancer of a type of blood cell normally involved in the body’s response to allergens and inflammation. MCT is the most common skin tumor in dogs; it can also affect other areas of the body, including the spleen, liver, gastrointestinal tract, and bone marrow. Mast cells contain granules filled with substances which can be released into the bloodstream and potentially cause systemic problems, including stomach ulceration and bleeding, swelling and redness at and around the tumor site, and potentially life-threatening complications, such as a dangerous drop in blood pressure and a systemic inflammatory response leading to shock. When MCT occur on the skin, they can occur anywhere on the body. The most common sites of MCT spread (metastasis) are the lymph nodes, spleen and liver.
When they occur on the skin, MCT vary widely in appearance. They can be a raised lump or bump on or just under the skin, and may be red, ulcerated, or swollen. In addition, many owners will report a waxing and waning size of the tumor, which can occur spontaneously, or can be produced by agitation of the tumor, causing degranulation.
The biological behavior of these tumors can vary widely; some may be present for many months without growing much, while others can appear suddenly and grow very quickly.
Melanomas are tumors arising from pigment cells within the body. In dogs, melanomas most commonly occur on the skin, in the mouth, and on the digits (toes) or in association with the nail bed. The majority of skin melanomas are benign in dogs, however oral and digit/nail bed melanomas tend to be malignant, with the potential to locally invade tissues and underlying bone, as well as spread to other parts of the body. Metastasis (spread) of melanoma, when it occurs, tends to be to regional/draining lymph nodes, and lungs; but it can also spread distantly to other organs, such as the liver. Dogs that develop melanoma tend to be older. The cause of melanoma is unknown in dogs.
Most melanomas in the mouth or skin will present as dark, raised masses. Some melanomas may appearas a pinkish color (amelanotic melanomas). In the mouth, they can be associated with drooling, halitosis (bad breath), bleeding from the mouth, difficulty eating or dropping food from the mouth, and oral pain. Those occurring on the digit or associated with the nail bed can be associated with toe swelling, loosening or infection of the affected toenail, or lameness on the affected leg.
Soft tissue sarcomas (STSs) consist of a variety of tumors that arise from mesenchymal cells. Tumors included in this group are fibrosarcomas, peripheral nerve sheath tumors, and hemangiopericytomas. They typically appear as firm, subcutaneous (under the skin) masses, which may be located on the extremities, trunk, or head and neck. They usually are slow-growing tumors, but may also come up quite quickly. These tumors are locally invasive, and are not likely to go to other sites (metastasize).
The most common tumor to originate in the liver is hepatocellular carcinoma. This is a slowly developing cancer. Many cases are treatable with surgery, but it will depend on the type and location of the tumor. In some cases, the tumor can be identified as a palpable mass in a dog’s stomach. Often dogs present the typical symptoms of liver disease, but some tumors can be non-symptomatic for quite some time. Eventually, the tumor will cause serious abdominal hemorrhage. This type of cancer is slow growing; however, left untreated, it will cause cell death and cirrhosis of the liver and eventually lead to end-stage liver disease.
Hepatocellular carcinoma is much easier to treat in the early stages. Take your dog to see a veterinarian if you notice any of the following symptoms. Decreased appetite Weight loss Lethargy Abdominal distention Mass can be felt in the stomach Vomiting Excessive thirst Frequent urination Bloody diarrhea Jaundice Ascites (fluid in the abdomen) Gastrointestinal bleeding Ulcers Hepatic encephalopathy (disorientation, circling, aggression, seizures coma).
Squamous cell carcinoma accounts for 5% of all cutaneous tumors found in dogs. These tumors generally grow slowly, but are aggressive in nature. They do not metastasize to the regional lymph nodes. They are usually found in those areas within the epidermis where there is a dearth of pigmentation, hair or a very sparse hair coat. The peak incidence of squamous cell carcinoma in the dog is between 6 and 10 years of age.
Most cutaneous squamous cell carcinomas appear as firm, raised, frequently ulcerated plaques and nodules; sometimes they can be extremely exophytic (outwardly growing) and have a surface that resembles a wart. These usually develop on ventral abdominal, preputial (exocrine glands present in front of the genitals), scrotal, and inguinal skin in white-skinned, shorthaired breeds such as Dalmatians, Bull Terriers, and Beagles. The appearance may vary from time to time. The clinical signs usually depend upon the location of the tumor. For instance dogs with tumors on their feet may limp.
Adenocarcinoma – They are type of tumors most often associated with cancer of the stomach. This cancer is one that is found in glandular tissue. It accounts for 70-80% of all malignancies. This type of cancer originates in the stomach wall and spreads to the gastric lymph nodes, omentum (fat on the bottom edge of the stomach), liver, oesophagus, adrenal glands, lungs, duodenum (first part of the intestine), pancreas and spleen. In some bizarre cases, gastric carcinoma is believed to have metastasized to the testes. Gastrointestinal stromal tumors (GIST) also account for 20% of all gastric tumors.
Lymphoma- It is a type of cancer that originates in the white blood cells (leukocytes). It is a multicentric type of cancer that is unfortunately the most common. But gastric lymphoma accounts for 7-24% of all deaths caused by cancer of the gastrointestinal tract in dogs. Is it important to state that Lymphoma Gastric cancer is not the most common Gastric cancer and should not be confused with Lymphoma cancer which is one of the most common Cancer in dogs.
Mast Cell Tumors – Mast cells are part of the immune system that responds to allergies and inflammations. They are present in the linings of the digestive tract, lungs, nose and skin. When these cells become abnormal they form mast cell tumours that release biological chemicals like heparin and histamine in excess. These chemical changes in the body cause damage.
Leiomyrosarcoma – They are type of tumors that are present on the walls of organs like stomach, bladder, uterus and the respiratory tract. They mostly metastasize to liver, spleen, kidneys and lymph nodes.
The symptoms an owner normally sees are vomiting tinged with blood, anorexia and loss of weight. Other symptoms include vocalization, licking or scratching of any part of the body, unhappy demeanour and body language, irregular urination and bowel movements. lt results from poor digestion, loss of blood and protein from the ulcer or generalized tumor cachexia. Duration of symptoms may vary from weeks to many months.
Primary brain tumors arise from the brain, spinal cord, and associated tissues -collectively known as the central nervous system (CNS). Primary brain tumors are categorized as benign (noncancerous) or malignant (cancerous). They are usually solitary, but multiple primary lesions have been reported. Primary brain tumors include meningioma, glioma, choroid plexus papilloma, pituitary adenoma or adenocarcinoma and others. Multiple meningiomas and cerebrospinal fluid (CSF, it is a clear bodily fluid in which the brain floats) metastases of medulloblastoma (it is a highly malignant primary brain tumor that originates in the cerebellum or posterior fossa) or choroid plexus carcinoma have been reported to occur in dogs. Extracranial (upper portion of the skull that protects the brain) metastases of primary brain meningiomas have been reported. They are usually slow growing because the brain is contained within the calvaria (roof of the skull). But they may have devastating effects. When the tumors grow slowly, they compress the brain gradually. The impact may not be palpable in this case, since our brain has a compensatory mechanism which helps it to adapt itself to the accentuating pressure. But when the mechanisms get exhausted, clinical signs appear.
Glial neoplasms have been broadly classified into various categories based on their variable morphology or appearance. Since 1990s, pathologists have been trying to establish that in addition to monocytic gliomas there are neoplasms comprising a mixture of two or more neoplastic glial cell types. Due to the anaplastic (less differentiated) nature of embryonal tumors, they have been consolidated under the single term- primitive neurorectodermal tumors (PNETs). It is believed that all embryonal tumors stem from a germinal neuroepithelial cell (sub-type of stem cells) that can differentiate along a number of neurorectodermal cell lines (start of a tissue that covers body surface. It differentiates to form the nervous system and the epidermis). They are usually malignant in nature.
Secondary brain tumors represent metastasis of a tumor to the brain from any other part of the body. The most widely seen secondary tumors of dogs include local extension of nasal adenocarcinoma, metastases from mammary, prostatic or pulmonary adenocarcinoma, metastases from hemangiosarcoma and extension of pituitary adenoma or carcinoma. These tumors have a very poor prognosis, since they have traveled through the body depositing clusters of abnormal tissues in their course. Nerve sheath lesions that originate from cranial nerves like the oculomotor nerve (controls most of the eye movements) and the trigeminal nerve (responsible for sensation in the face) may also occur in dogs. Skull lesions that affect the brain by local extension include osteosarcoma (most common type of primary malignant bone tumor), chondrosarcoma (type of bone cancer) and multilobular osteochondrosarcoma (uncommon tumor that affects the skull).
Although brain tumors can affect any breed at any age, they are most frequent in older dogs. Breeds over 5 years of age are highly predisposed. Certain breeds also have relatively higher incidence. Glial cell tumors and pituitary tumors are most common in brachycephalic (dogs with short, broad heads) breeds, while meningiomas are most frequently seen in dolicocephalic (dogs with long narrow skull) breeds.
Symptoms– Many dogs with brain tumors show vague signs like changes in behavior. These symptoms are so negligible, that owners and vets tend to overlook them till signs of brain dysfunction are well developed. These include subtle behavior alterations, that usually develop over months and years. Like humans, dogs may also develop severe headaches, but since they cannot articulate, symptoms like decreased frequency of barking or diminished levels of activity.
The most prominent signs associated with a brain neoplasm in dog is seizures, especially if it occurs in the animal after 4 years of age. It could either be a generalized seizure or a focal seizure. Other clinical signs frequently associated with a brain tumor in dogs include circling, altered posture, gait abnormalities, ataxia (loss of the ability to coordinate muscular movement), head tilt, behavior change, depression, incontinence (inability to control excretory functions) and cervical spinal hyperesthesia (abnormal increase in sensitivity to stimuli of the senses).
If the neoplasm involves the brain stem cranial nerve, deficits are seen like weakness, sensory loss, vision problems, hearing or smell. Weakness and loss of energy usually indicate a tumor in the cerebral frontoparietal or sensory motor regions. Vision problems denote lesions in the visual pathways from the optic nerve to the occipital lobe of the cereberum. Difficulties in smelling are associated with tumors in the cribriform plate, olfactory bulb and peduncle (band of neurons that connect various parts of the brain) and pyriform (pear shaped neural structure on either side of the brain) or temporal lobes of the cereberum. Difficulties in balance or gait are due to cerebellar or vestibular (contributes to balance and sense of spatial orientation) involvement.
Increased intracranial pressure are indications of tumor expansion. The symptoms consist of lethargy, irritability, lethargy, head pressing, compulsive walking, altered states of consciousness, or associated locomotor disturbances (inability to move from one place to another).
Malignant histiocytosis, or disseminated histiocytic sarcoma, is a fairly rare and aggressive disease that produces multiple cancerous tumors in the skin and vital organs throughout the body. These tumors progress rapidly and are very often fatal, as they spread to various organs and destroy the surrounding tissues. Symptoms are varied and depend on what part of the body is affected. A disease affecting middle aged dogs, malignant histiocytosis produces multiple tumors in the skin on the limbs or trunk. Inside the body, tumors frequently affect many organs systems simultaneously, including the spleen, liver, lymph nodes, lungs, bone marrow, brain and central nervous system, and joints. It is important for this condition to be diagnosed and treated immediately, as it can quickly result in life-threatening conditions.
The definitive cause of malignant histiocytosis is still unknown. While some believe that these tumors are a soft tissue sarcoma, others have categorized malignant histiocytosis as a type of histiocytic sarcoma, which may be influenced by an abnormally large amount of histiocytes, a type of white blood cells that are integral to immune system functions.
Many different types of symptoms can be involved in this disease, and are wholly dependent on which organs are affected by tumor growth. If the lungs are affected, breathing can be difficult, while a mass in the brain can result in seizures and paralysis. Be sure to note all the symptoms you see so that your veterinarian will have an accurate view of which organs may be involved. Some signs can include: Loss of appetite, Weight loss, Vomiting, Fever, Lethargy, Depression, Coughing, Difficulty breathing, Diarrhea, Limping, Lameness, Incoordination, Neurological disturbances, Paralysis, Seizures, Anemia, Jaundice.
Male dogs are subject to prostate disease (also known as prostatomegaly). An enlarged prostate can affect middle-aged to senior, male dogs of any size or breed. The prostate is a gland that normally lives inside the pelvis, behind the bladder and below the rectum. Normally, the prostate reaches its maximum size by the time a dog is two years old. When a dog is neutered before puberty, the prostate gland does not develop due to the lack of testosterone (the male hormone produced by the testicles). This is no problem for dogs since the prostate's main job is to support and carry sperm cells. Also, when a mature dog is neutered, the prostate will actually shrink. This means that a neutered male dog's risk for prostate disease is greatly decreased, even after puberty.
In a dog the enlarged prostate will usually push up on the rectum, causing painful or difficult defecation. Stool may be ribbon-shaped. This is a classic sign of an enlarged prostate.
Dogs will also often walk abnormally, as if they are "walking on eggshells." Dog guardians may observe pets straining to urinate, or a discharge of blood or pus from the penis. It is important to remember, however, that dogs with prostate disease may show no signs whatsoever.
Transitional Cell Carcinoma (TCC) , Cancer of the urinary tract in dogs, is a malignant tumor that develops from the transitional epithelial cells that line the bladder. In dogs, this tumor invades into the deeper layers of the bladder wall including the muscle layers. As the cancer enlarges in the bladder, it can cause obstruction to the flow of urine from the kidneys to the bladder or from the bladder to the outside of the body. Canine TCC also has the ability to spread to lymph nodes and to other organs in the body (lung, liver, others). TCC most frequently is found in the bladder, but can also develop in the kidneys, ureters, prostate, and urethra.
Signs and symptoms: Blood in the urine, straining to urinate, and making repeated frequent attempts to urinate are the most frequent signs of TCC in dogs. Pet owners must realize, however, that a urinary tract infection will cause these same symptoms, so the symptoms alone do not necessarily mean the dog has TCC. Less commonly, dogs with TCC can have lameness due to spread of the tumor into the bones or spread into the lungs and a paraneoplastic syndrome called hypertrophic osteopathy.
- Abnormal lumps or swellings that persist or continue to grow
- Sores that do not heal
- Weight loss
- Loss of appetite
- Chronic bleeding or discharge
- Difficulty eating or swallowing
- Loss of stamina, reluctance to exercise and play
- Chronic lameness or stiffness that implies discomfort
- Difficulty breathing, urinating, or defecating