Salivary gland tumors are rare in dogs and cats. The mandibular and parotid glands are most commonly affected. Older dogs and cats, Poodle and Spaniel breed dogs and Siamese breed cats, and male cats are at a higher risk for salivary gland tumors. The most commonly reported salivary gland tumor is the adenocarcinoma. Signs include swelling of the upper neck or ear base, halitosis, anorexia, weight loss, difficulty eating, pain, and lethargy. Fine needle aspiration may be used to differentiate between neoplastic and non-neoplastic masses. Biopsy provides a definitive diagnosis. General staging as well as CT scan or MRI are recommended since these tumors have a tendency to be locally invasive and metastasize. The treatment of choice is usually surgical excision. If complete excision is not possible, adjunct radiation therapy may be pursued.
Soft tissue sarcomas are a broad category of tumor types. These tumors can arise anywhere there is soft tissue, including the limbs, joints, face, intestine and reproductive tissues. Routine staging is recommended to help dictate therapy. If surgery is possible, wide-surgical excision is pursued. If removal is incomplete or not possible, adjunct radiation therapy can be pursued. Metronomic chemotherapy may provide benefit in patients when few options exist.
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 the 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.
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.
Skin gland, hair follicle, and sebaceous gland tumors are more commonly found to be benign. Matrical carcionoma 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 initial surgical removal and histopathology. In the majority of cases, surgery is recommended and other treatments are unnecessary. Chemotherapy and/or radiation therapy in pets with matrical carcinomas or sebaceous gland adenocarcinomas may be recommended.
The three most common testicular tumors are seminomas, Sertoli cell tumors, and interstitial cell tumors. Though other tumor types are possible, testicular tumors as a whole are generally not aggressive and have a low metastatic rate. Pets that are cryptorchid are predisposed to the development of Sertoli cell tumors and seminomas. 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.
Thyroid tumors can be benign or malignant and functional or nonfunctional. In dogs, they are usually malignant and nonfunctional, whereas in cats, they are usually benign and functional. A swelling in the neck may be the only sign in a dog, however a change in bark, coughing, difficulty swallowing, facial swelling, rapid breathing, breathlessness, weight loss, and a loss of appetite are possible. In cats, the signs are related to excess thyroid hormone production (hyperthyroidism). Thyroid tumors are diagnosed with a physical examination, bloodwork, various forms of diagnostic imaging, and in dogs, a tissue biopsy. In dogs, staging is required to determine the presence of spread. A variety of treatment options are available. These include surgery, radiation, chemotherapy, and radioactive iodine therapy in dogs, and medication, radioactive iodine therapy, surgery, and dietary therapy in cats. With appropriate treatment, the prognosis for dogs and cats with thyroid tumors is good.
Urinary tract tumors can occur anywhere along the urinary system, from the kidneys to the urethra. They are more likely to be malignant than benign. In dogs, the most common type of urinary tract tumors are bladder tumors, and of these, the most common is transitional cell carcinoma (TCC). Lymphoma and renal carcinoma are the two most common primary kidney tumors in cats and dogs, respectively, but these are relatively rare. Staging is recommended with all urinary tract tumors. With TCC, staging should include X-rays of the spine and/or hips since bone metastasis is possible. With bladder tumors, treatment is usually medical (e.g., NSAIDs) with/without chemotherapy and radiation therapy. With unilateral kidney tumors, nephrectomy is usually the treatment of choice, while with bilateral kidney tumors, chemotherapy may be considered. Treatment and prognosis always depend on the type of tumor and degree of local invasion and metastasis.
Uterine tumors are quite rare in North American pets, mainly due to routine spaying practices. Several types of tumors can arise from the tissues of the uterus. How the tumor will affect your pet is entirely dependent on the location and type of tumor. By far, uterine cancer is most commonly diagnosed by abdominal ultrasound or during a spay procedure. Full staging is recommended prior to surgery to determine if the cancer has metastasized. Treatment for solitary masses without evidence of spread typically involves ovariohysterectomy. If metastasis is present, chemotherapy should be considered, however its efficacy is not completely known. Without evidence of spread, uterine tumors carry a good prognosis.
Vascular tumors of the skin develop from the blood vessels of the skin. These tumors may arise anywhere on the body and appear as a firm and raised lump on or under the skin. Hemangiomas may ulcerate and bleed; hemangiosarcomas may bleed into the surrounding tissues. This type of tumor is typically diagnosed via a tissue biopsy or surgical removal of the entire tumor. Surgery is the recommended treatment for vascular tumors of the skin.