Cutaneous lymphoma is another round cell tumor of dogs.
While lymphoma is a common cancer in dogs, the cutaneous form is actually quite rare, accounting for only about five percent of all canine lymphoma cases.
Two forms of canine cutaneous lymphoma exist: epitheliotropic and nonepitheliotropic. In humans the epitheliotropic form is also called mycosis fungoides because of the mushroom appearance of the lesions in people.
In dogs, however, the cancer is more likely to appear as one or more areas of widespread inflammation. Typically, multiple areas of skin are involved. Because the common age of onset of cutaneous lymphoma in dogs is five to eleven years, these patients may have had a history of chronic skin lesions in the past.
Common locations include the junction of mucus membranes and skin, so the mouth, eyes, rectum, vulva and prepuce may be affected.
Metastasis to nearby lymph nodes frequently occurs, so lumps in those areas are often associated with this disease. Systemic disease signs may be present if other organs, such as the liver, kidneys or spleen have been seeded by tumor cells
In cats, the nonepitheliotropic form of cutaneous lymphoma is the more common, but this form is even more rare in dogs. One or more lesions may appear, and patients find them to be very itchy.
Treatment is mainly palliative due to the extremely poor prognosis of this disease. Single lesions may respond to radiation, and chemotherapy may buy time for the patient, although resistance to multiple chemotherapeutic agents is common.
See you tomorrow, Dr. Randolph.