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Illustrated Articles

Cats + Cancer & Tumors

  • Clinical signs of pituitary tumors depend on whether the tumor is functional or non-functional. Functional tumors can cause Cushing's disease in dogs and can cause acromegaly and insulin-resistant diabetes in cats. Non-functional pituitary tumors can enlarge to cause neurological signs. Diagnosis is based on the history, bloodwork, urinalysis, and sometimes a CT scan or MRI. Medical therapy is often the treatment of choice for functional tumors. Radiation therapy is another option and is usually the primary treatment for non-functional tumors.

  • Plasma cell tumors develop as a result of dysregulated production of plasma cells and are relatively uncommon in dogs and cats. Some plasma cell tumors are benign and the most common locations for these tumors are the head, feet, lips, mouth, and ears. The treatment of choice for benign plasma cell tumors is surgical removal, with little to no recurrence if completely excised. Conversely, multiple myeloma is a very malignant cancer that is usually treated with chemotherapy.

  • Pleural effusion refers to the abnormal accumulation of fluid within the chest cavity. The fluid is not found within the lungs, but instead within the pleural sac, essentially meaning the lungs are floating in a chest that is full of fluid. Several conditions can cause pleural effusion, including chylothorax, heart failure, and tumors in the lungs or chest wall. Immediate treatment often requires oxygen support and the removal of the excess fluid by thoracocentesis, which can also then be tested to diagnose the cause of the pleural effusion. Treatment and prognosis vary depending on the underlying cause of the pleural effusion.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.