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Cancer & Tumors + English

  • Lymphoma is a cancer of the lymphocytes. Lymphocytes are cells that are involved in the immune system. Feline lymphoma most commonly affects the intestines; therefore, clinical signs of lymphoma are often similar to other intestinal diseases. Diagnosing lymphoma requires finding cancerous cells on microscopic examination. This cancer cannot be prevented, but the likelihood of a cat developing lymphoma can be decreased by preventing feline leukemia virus infection.

  • A mammary tumor develops because of abnormal replication of the cells that make up the breast tissue. In cats, most mammary tumors (80-96%) are malignant. Sexually intact cats have a seven-fold increased risk for mammary tumors compared to spayed cats. Detecting and treating these tumors when they are small, and prior to metastasis, provides your cat with the best chance of long-term control. Surgery is by far the best treatment and, given the high metastatic rate in these tumors, chemotherapy is typically pursued afterward.

  • Mast cells are a type of white blood cell that plays a large role in allergic response through degranulation. Mast cell tumors (MCT) can occur in the skin, spleen, or gastrointestinal tract of cats. Their cause is unknown; however, many affected cats show a genetic mutation in the KIT protein involved in replication and cell division. Cutaneous MCTs most often appear as hard pale/white plaques or nodules, often around the head and they may be itchy. Splenic MCTs cause decreased appetite, weight loss, and vomiting. Intestinal MCTs may cause GI upset and bloody stools, and a mass may be palpable. Diagnosis is typically achieved via fine needle aspirate although histopathology can be used. Treatment usually requires surgical removal of the masses or the spleen. Sometimes, chemotherapy or radiation is needed.

  • Squamous cell carcinoma in situ is a disordered growth of the skin epidermis that may extend to include epithelium of the upper part of the hair follicles.

  • In some cases, chronic inflammation of the nose (rhinitis) leads to proliferation (hyperplasia) and formation of polyps in the nose or throat. These polyps are not cancerous but may need removal.

  • Neuroendocrine tumors are a group of tumors that develop from the cells of the neuroendocrine system, and include insulinomas, gastrinomas, glucagonomas, carcinoids, medullary thyroid carcinomas, small-cell lung carcinomas, pheochromocytomas, chemodectomas, and Merkel cell carcinomas. Some of these tumors are functional, while others are non-functional. The signs of disease in dogs and cats depend on the type of growth, location of the tumor, its size, the degree of infiltration in the surrounding tissues, whether it has metastasized, and whether it is functional. A definitive diagnosis requires tissue biopsy and histopathology, often with histochemical staining and electron microscopy. Staging is highly recommended for these tumors. Treatment may involve surgery, chemotherapy, radiation therapy, and medical and dietary management.

  • Odontogenic fibromas, sometimes previously referred to as an epulis, are benign tumors of the mouth often at the front of the upper jaw. These may be locally invasive and may cause some oral pain. Surgery is the recommended course of action to treat this condition.

  • Squamous cell carcinomas are malignant cancers originating from the lining cells of the mouth. They are locally invasive and often recurrent.

  • Fibrosarcomas are the second most common oral tumor in cats and arise from the fibrous and connective tissues of the oral cavity. These tumors are very invasive locally and are often difficult to manage, Diagnosis is based on biopsy and treatment involves surgery and occasionally radiation or chemotherapy. Palliative care with pain relief and antibiotics are essential to improve quality of life.

  • The most common oral tumor seen in cats is squamous cell carcinoma; the second most common is fibrosarcoma. This handout discusses the clinical signs, diagnosis and treatment of oral tumors in cats.