Educational Articles
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This handout explains post-vaccination sarcomas (also called injection-site sarcomas) in cats. They are a rare consequence of vaccine injections (and other drugs or materials) that can cause a very aggressive form of cancer at the site of the injection. The incidence of this condition, as well as precautions you and your veterinarian can take, are highlighted.
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Tumors of the prostate are relatively uncommon in dogs and extremely rare in cats. Clinical signs include bloody urine, or straining to urinate or defecate. Metastasis to the pelvic bone and/or lumbar spine is likely. Diagnosis and treatment options are discussed. Prognosis is considered poor.
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Radiation is a type of energy produced naturally by the sun, earth, and rocks and artificially by machines. Although several types of tumors can be treated with radiation therapy alone (e.g., nasal tumors, brain tumors, and certain types of lymphoma), radiation therapy is most commonly used to destroy or limit the growth of cancer cells left behind (i.e., microscopic disease) after a tumor has been surgically removed. Side effects depend on the type and location of the tumor and its surrounding tissues.
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Salivary gland tumors are rare in dogs and cats. The mandibular and parotid glands are most commonly affected. Signs include swelling of the upper neck or ear base, halitosis, anorexia, weight loss, difficulty eating, pain, and lethargy. The treatment of choice is usually surgical excision. If complete excision is not possible, adjunct radiation therapy may be pursued.
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A seizure is a sudden surge in the electrical activity of the brain causing signs such as twitching, shaking, tremors, convulsions, and/or spasms. Epilepsy is used to describe repeated episodes of seizures. With epilepsy, the seizures can be single or may occur in clusters, and they can be infrequent and unpredictable or occur at regular intervals. Since many different diseases can lead to seizures, it is important to perform diagnostic tests to investigate the underlying cause of the seizures. Treatment of seizures in the cat depends on the nature of the underlying disease.
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Soft tissue sarcomas are a broad category of tumors that can develop over the chest, back, side, legs, and facial tissues of your pet. The clinical signs depend on where the tumor is located and the tissues that are affected. Often, pets have a noticeable mass that is growing in size. One of the biggest concerns with soft tissue sarcomas is their ability to invade the local surrounding tissues. The most commonly pursued treatment is surgery. Chemotherapy is not usually pursued as a primary treatment unless surgery or radiation are not options for your pet based on the tumor size or location.
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Squamous cell carcinoma (SCC) is a tumor of the cells that make up the contact or upper layer of the skin. UV light exposure has been described as a developmental factor in people and appears to be associated with its development in cats. Areas affected include the ear tips, skin, toes, or peri-ocular region. Fine needle aspiration or biopsy may be performed for diagnosis. The metastatic rate does not appear overly clear, though staging is always recommended. SCC of the toe can occur as a primary tumor or may have spread from the lung (lung-digit syndrome). Surgery is almost always recommended in any case of SCC; the role of chemotherapy is controversial. Radiation therapy has an excellent response rate in cats with the SCC affecting the nasal planum and may give long-term tumor control.
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Stomach tumors are uncommon in dogs and cats. There are many kinds, including leiomyosarcomas, lymphomas, adenocarcinomas, mast cell tumors, fibrosarcomas, plasmacytomas, gastrointestinal stromal tumors (GISTs), and carcinoids (all malignant); and leiomyomas, adenomatous polyps, and adenomas (benign). Most tumors are malignant. Stomach tumors are more prevalent in older animals, males, and certain breeds. The signs of stomach tumors include chronic vomiting, inappetence, lethargy, and weight loss. Sometimes tumor ulceration will cause anemia. Paraneoplastic syndromes are possible with the muscle tumors. Stomach tumors may be diagnosed with imaging, endoscopy, or surgery, with a biopsy. Treatment may involve surgery, chemotherapy, or radiation therapy.
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Skin gland, hair follicle, and sebaceous gland tumors are often benign. Matrical carcinoma and sebaceous gland adenocarcinoma are rare and more aggressive forms of the disease. Regardless of the type (sweat, hair, or sebaceous) diagnosis is made by fine needle aspiration, biopsy, and/or surgical removal and histopathology. Further treatment is reviewed.
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Testicular tumors are generally not aggressive and have a low metastatic rate. Pets with undescended testicles (cryptorchid) are predisposed to the development of certain testicular tumors. Hyperestogenism is possible with Sertoli cell tumors. In any cryptorchid pet, removal of both testicles should be pursued. Intraabdominal tumors in cryptorchid pets may cause lethargy, decreased appetite, and fever. Standard staging is recommended in all cases, including a rectal exam. Surgery is typically the treatment of choice and may be combined with radiation therapy or chemotherapy if metastasis is evident.