Lymphoma or lymphosarcoma is a cancer of lymphocytes which are specialized white blood cells where they divide uncontrollably. This is the most common form of cancer associated with blood cells.    Dogs having this disease might show symptoms like enlarged lymph nodes, loss of appetite, and lethargy while others may be asymptomatic.  The presence of cancerous lymphocytes in the lymph nodes is an indication of lymphoma which is detected either by aspirate or biopsy sample. To assess the extent of the disease, a chest x-ray, abdominal ultrasound, and bone marrow evaluation are performed. Luckily, this type is of cancer is most responsive to chemotherapy treatment. You can consult with the veterinarian regarding the treatment options available and what to expect with treatment.   The prognosis of the disease depends on the stage of cancer, how the animal responds to the chemotherapy, and feline leukemia (FeLV) status, in the case of cats.