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Cancer & Tumors

  • Chondrosarcomas arise from cartilage, which is a connective tissue primarily found where bones meet with joints, as well as at other locations in the body such as the nasal cavity, and ribs. Chondrosarcoma is the second-most common primary bone tumor in dogs. Canine chondrosarcoma most commonly affects the flat bones of the body, such as the ribs, skull, nasal cavity, and pelvis, although the limbs can also be affected. Aggressive surgical removal is typically recommended, although radiation therapy may also be used, depending on location of tumor. Metastasis may occur but is relatively uncommon.

  • Cornifying epitheliomas are benign skin tumors that are secondary to keratin buildup. They can develop anywhere but may be most troubling if they affect the skin around the nail, causing swelling, discomfort, and lameness. Surgical removal is curative in most cases.

  • A cutaneous histiocytoma is a common benign (harmless) tumor of the skin in dogs, typically younger ones. Their development, appearance, diagnosis, and treatment are explained in this handout.

  • Cutaneous histiocytosis is an uncommon condition in dogs. It is a non-cancerous increase in the number of reactive cells (histiocytes) caused by an immune system dysfunction. It generally manifests as multiple bumps and nodules confined to the dog's skin. The clinical signs, diagnosis, and treatment of this condition are explained in this handout.

  • Lymphoma is a type of cancer that is common in cats. When it occurs in the skin, it is called cutaneous lymphoma, but this form is quite rare. Feline cutaneous lymphoma can present various clinical signs, including itching, alopecia (hair loss), scaly skin, skin redness, loss of skin color, ulcers, nodules, pustules, and plaques.

  • Lymphoma is a type of cancer that is common in dogs. When it occurs in the skin, it is called cutaneous lymphoma, but this form is quite rare. Canine cutaneous lymphoma can present various clinical signs, including itching, alopecia (hair loss), scaly skin, skin redness, loss of skin color, ulcers, nodules, pustules, and plaques.

  • Collecting tissue samples for cytology or histopathology allow a pathologist to often give a diagnosis of the type of mass or tumor your pet has. Samples can be obtained by fine needle aspirate or biopsy, where a piece of the mass is cut out. Based on what the mass appears like under the microscope, the pathologist can often give a prognosis of how the tumor will behave.

  • Ear canal tumors are abnormal growths that can develop from any part of the ear canal (the skin, the glands of the skin that produce earwax and oil, and the underlying connective tissues, muscles, and bones). Initially, these tumors may appear as one or more pink, white, or purple nodular masses in the ear canal. If benign, they may grow to a certain size and may or may not be problematic. If malignant, they may grow, ulcerate (break open) and bleed, and nearly always become infected, causing recurrent or chronic ear infections. The treatment of choice for ear canal tumors is surgical excision.

  • Esophageal tumors are extremely rare but more often than not malignant type tumors. The cause is unknown but cases in tropical environments may be due to infection by the worm Spirocerca lupi. Treatment options are limited as surgical complications are high due to the advanced nature of the disease at time of diagnosis.

  • Eye melanomas in cats may be benign or malignant (cancerous). Malignant tumors, called diffuse iris melanomas, show up as multiple spots of color change in the iris, while benign tumors, called limbal melanomas, present as a distinct mass at the edge of the cornea. The diagnosis of these tumors is largely by clinical signs and tumor appearance. Treatment for diffuse iris melanomas may include close monitoring, laser surgery, removing part of the iris (iridectomy) and removing the eye (enucleation). Metastasis has been reported in about 19-70% of cases of diffuse iris melanoma, with most spread to the regional lymph nodes, kidneys, liver, and lungs. Treatment for limbal melanomas may include close monitoring, and surgery, sometimes combined with cryosurgery, laser surgery, or radiation therapy. Enucleation is an option if the treatment is unsuccessful, or the tumor regrows.