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Dogs + Tumors + English

  • Hepatoid gland tumors are a type of cancer that develop from the sebaceous (sweat) glands of the skin. The most common location for these tumors to develop is the perianal area, and the most common tumor is the perianal adenoma. Perianal adenocarcinomas, and rarely perianal epitheliomas may also occur. These tumors appear as one or more small, round, pink, hairless, slow-growing nodules around the anus, and can sometimes ulcerate and become infected. Malignant tumors can grow much bigger and faster, invade the underlying tissue, and metastasize. Diagnosis may be made by fine needle aspiration, biopsy, or full excision of the tumor. Staging is recommended for adenocarcinomas. Treatment may involve surgical removal along with neutering, cryotherapy, laser ablation, radiotherapy, chemotherapy, and occasionally hormone therapy. The prognosis is good with perianal adenomas, fair to poor with adenocarcinomas, and generally good with epitheliomas.

  • Infertility in a female dog is defined as the inability to conceive and deliver viable puppies, even when mated multiple times with a known fertile male surrounding the time of ovulation. This handout outlines the varying causes of infertility in female dogs and how they may be diagnosed and treated.

  • Intestinal tumors are uncommon in dogs and cats. There are many kinds, including leiomyosarcomas, lymphomas, adenocarcinomas, mast cell tumors, GISTs, plasmacytomas, carcinoids, and osteosarcomas (all malignant) and leiomyomas, adenomatous polyps, and adenomas (all benign). Most intestinal tumors are malignant. Intestinal tumors are more prevalent in older animals, males, and certain breeds. The signs of intestinal tumors vary according to the area of the intestinal tract that is affected, and can include vomiting, lack of appetite, lethargy and weight loss for the upper bowel and difficulty defecating, ribbon-like stools, and rectal prolapse with the lower bowel. Sometimes tumor ulceration causes anemia. Paraneoplastic syndromes are possible with the muscle tumors. Intestinal tumors may be diagnosed with imaging, endoscopy, or surgery, with a biopsy. Treatment may involve surgery, chemotherapy, or radiation therapy.

  • Primary liver tumors in dogs and cats are rare. There are 4 types: hepatocellular tumors, bile duct tumors, neuroendocrine tumors, and sarcomas. These cancers can be massive, nodular, or diffuse in form. In dogs, most liver tumors are malignant, while in cats, most are benign. The signs of liver tumors range from being asymptomatic to having inappetence, fever, lethargy, and weight loss; and less commonly, nausea, vomiting and diarrhea; increased drinking and urination; and jaundice. Occasionally there are neurological signs, such as seizures. With tumor rupture and intrabdominal bleeding there may be weakness, collapse, and difficulty breathing. The diagnosis is based on history, clinical signs, exam findings, diagnostic imaging, and FNA or liver biopsy. A biopsy is best for a definitive diagnosis. Surgery is the treatment of choice for most primary liver tumors followed by chemotherapy. Chemoembolization is a newer treatment.

  • Lung tumors are considered rare in cats and dogs. Certain breeds are more predisposed to develop pulmonary tumors than others. Not all pets with pulmonary tumors exhibit clinical signs and are often diagnosed incidentally from routine chest X-rays. Ultrasound-guided fine needle aspiration or biopsy will confirm the diagnosis. Pulmonary carcinomas have a high tendency to metastasize, so full staging is recommended. Surgery is by far the most common treatment, though radiation therapy may be considered if surgery is not possible.

  • Lymphatic tumors are rare in pets. Lymphangiomas are benign and lymphangiosarcomas are malignant and have a moderate-to-high metastatic potential. Patients with lymphatic tumors typically have severe edema because of lymphatic obstruction. These types of tumors occur more frequently in young dogs and cats. Treatment usually involves surgical excision and chemotherapy may be used as a follow-up treatment in the case of lymphangiosarcomas.

  • Lymphoma is a cancer of the lymph nodes and lymphatic system. This cancer may be localized to one particular region, or may spread throughout the entire body. Lymphoma is a relatively common cancer, accounting for 15-20% of new cancer diagnoses in dogs. The prognosis for lymphoma varies, depending on various characteristics that can only be determined by specialized testing.

  • The most common forms of cutaneous lymphoma are epitheliotropic lymphoma and dermal lymphoma. No specific risk factors or causes have been identified in the development of cutaneous lymphoma. Generally, cutaneous lymphoma can appear as various-sized irritated, ulcerated, or infected patches anywhere on the skin, including the gums, nose, or lip margins. These areas may become ulcerated and bleed, or become crusted. Secondary infections are possible. By far, the most common treatment for cutaneous lymphoma is chemotherapy. Unfortunately, the response to treatment, although initially encouraging, is typically short-lived, with gradual return of the tumors.

  • There are several different types of malignant mammary tumors, with carcinomas being the most common. Carcinomas arise from epithelial (skin) cells, tubules of the mammary glands, or other cells found in the mammary chain. The size of the masses and their appearance may vary, but they are usually firm and nodular. Occasionally, the skin over the mass may ulcerate (open) and bleed, and the affected area may feel warm to the touch and become painful. Detecting and treating these tumors when they are small, and before spread has occurred, will provide your dog with the best chance for long-term control.

  • Mast cell tumors are most common in the skin of dogs and have a nodular, alopecic, sometimes inflamed appearance. These can be itchy and can fluctuate in size. They are generally easily diagnosed by fine needle aspirate but histopathology is needed to grade the tumor to determine the prognosis and best management. Tumors can range from lower-grade, with minimal metastasis and spread, to higher-grade, with a high risk of metastasis and local invasion. Treatment usually involves surgical removal with wide margins and, depending on complications, may require supportive treatment including chemotherapy, radiation therapy, and therapy to target the mutation that instigated the tumor.