Mammary tumors in cats are not very common in North America due to routine spay procedures. Hormones play a role in tumor development in cats. Cats spayed prior to 6 months of age have a reduced risk of developing mammary tumors. Siamese Cats appear to be predisposed to developing mammary tumors. Mammary tumors are typically not painful and are usually discovered during a routine physical examination. Staging is recommended in all cases due to the tendency for these tumors to metastasize. Surgery is typically the treatment of choice and chemotherapy may be recommended after surgery.
A mast cell tumor (MCT) is a type of tumor consisting of mast cells. Mast cell tumors can form nodules or masses in the skin (and other organs), and cause enlargement of the spleen and intestine. Most mast cell tumors are seen as firm plaques or nodules in the skin. If your cat has the splenic form of the disease, the most commonly observed signs are weight loss, vomiting, and loss of appetite. The intestinal form, depending on how severe the disease is, may cause vomiting, diarrhea, fresh red blood in the stool, or black/tar-colored stool. This cancer is typically diagnosed via fine needle aspiration or biopsy. Surgical removal of the mass is the treatment of choice. Radiation therapy may also be suggested.
Mast cells originate or are formed in the bone marrow but complete their maturation in peripheral tissues. They are found in all tissues of the body but are concentrated in the skin, respiratory tract and digestive tract.
Melanocytes are cells that produce a pigment called melanin. A melanoma is an abnormal production of these cells in a dysregulated manner that forms a nodule, mass, or other form of lesion. Melanomas of the skin may develop anywhere on the body and are not typically bothersome. Toe melanomas, however, can be much more painful and concerning for your pet's health. Melanomas are often black in color but some do not produce pigment (amelanotic melanoma). Fine needle aspiration or biopsy may be used for diagnosis. Melanomas of the skin and toes are treated surgically and radiation therapy may be discussed.
The phrase 'multidrug resistance mutation 1 (MDR1)' refers to a specific mutation that can occur at a gene known as the MDR1 gene, also known as the ABCB1 gene. Many herding breeds (most commonly Collies and Australian Shepherds) have a mutation at the MDR1 gene that makes them more sensitive to the negative effects of certain medications.
The two most common nasal tumors are nasal adenocarcinoma and nasal lymphoma. Clinical signs range from mild to severe, and may include respiratory distress, hemorrhage, and neurological problems. Staging is always recommended before primary therapy is pursued. Radiation therapy is usually pursued for localized disease. Chemotherapy is usually pursued for systemic disease.
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.
Oral papillomas (warts) are benign tumors of the epithelial lining of the mouth and throat caused by papillomaviruses. The esophagus may also be affected in severe cases.
Peripheral odontogenic fibroma (formerly known as fibromatous and ossifying epulis) is a benign, often slow-growing tumor that arises from periodontal structures. They can be further sub-classified as peripheral odontogenic fibromas and acanthomatus ameloblastomas. These tumors do not spread to other organs; however, extension to surrounding tissues is common. Treatment is dependent on size and location of the tumor. If surgery cannot be performed, radiation therapy is an excellent alternative for ameloblastomas given their high degree of response to radiation therapy.
Oral squamous cell carcinomas (SCC) are the most common oral tumor in cats, and second most common in dogs. These tumors are locally aggressive, with a possibility to metastasize. Regardless of the location of SCC, surgery is the typically the standard treatment. Radiation therapy may be recommended following surgery or as a primary treatment for palliative care. Staging is recommended for all cases. If metastasis is present chemotherapy is often pursued.