The most common initial symptom of multicentric lymphoma in dogs is firm, enlarged, non-painful lymph nodes. A lymph node affected by lymphoma will feel like a hard, rubbery lump under your dog’s skin. The most easily located lymph nodes on a dog’s body are the mandibular lymph nodes (under the jaw) and the popliteal lymph nodes (behind the knee). Other common symptoms include loss of appetite, lethargy, weight loss, swelling of the face or legs (edema), and occasionally increased thirst and urination. The photo on the left shows a dog with edema of the left rear leg. This is caused when a swollen lymph node blocks the normal drainage of fluid from the leg.
Cutaneous lymphoma tends to appear first as dry, flaky, red, and itchy patches of skin anywhere on the body. As the disease progresses, the skin becomes moist, ulcerated, very red, and thickened. Masses in the skin can also occur with cutaneous lymphoma. Cutaneous lymphoma may progress slowly and often has been treated for several months as an infection or allergy before a diagnosis of lymphoma is made. Cutaneous lymphoma may also appear in the mouth, often affecting the gums, lips, and the roof of the mouth. Cutaneous lymphoma in the mouth is often mistaken for periodontal disease or gingivitis in its early stages. The photo on the left shows cutaneous lymphoma in the mouth of a dog.
Dogs with gastrointestinal lymphoma usually have symptoms such as vomiting, watery diarrhea, and weight loss. The diarrhea is often very dark in color and foulsmelling.
Dogs with mediastinal lymphoma typically have difficulty breathing. This may be due to the presence of a large mass within the chest or due to the accumulation of fluid within the chest (pleural effusion). Affected dogs may also show swelling of the face or front legs as well as increased thirst and urination.