CONDITION
Multicentric Lymphoma in Dogs
Multicentric lymphoma is a condition in which lymphocytes—white blood cells that normally patrol the body as part of the immune system—begin to multiply in an uncontrolled way within the lymph nodes. These nodes, which sit at junctions throughout the body, become visibly enlarged. In dogs, this form of lymphoma tends to affect multiple node groups at once, which is why it carries the name multicentric. Owners often first notice firm, painless swellings under the jaw, in front of the shoulders, or behind the knees. The dog may otherwise seem well in the early stages, or there may be quieter signs such as reduced appetite, weight loss, or a general sense that energy has dipped. Because the nodes themselves are not usually tender, the swelling can be present for some time before it prompts concern. This page explores what these swellings may signal, what is happening within the lymphatic system, how the condition is investigated through examination and laboratory work, and the range of approaches that exist once a picture has formed. The goal is orientation, not instruction—understanding the landscape so that conversations with your veterinary team can be as clear and grounded as possible.
Why this matters now
Multicentric lymphoma in dogs tends to appear in middle-aged to older animals, with most cases diagnosed between six and nine years of age. Certain breeds—including Golden Retrievers, Boxers, Bullmastiffs, and Scottish Terriers—appear more frequently in clinical records, though the condition can arise in any breed or crossbreed. There is no single environmental trigger that has been conclusively identified, and the reasons why lymphocytes begin to proliferate in this uncontrolled way remain an area of active investigation.
The course of multicentric lymphoma is variable, but without intervention it often progresses over a period of weeks to a few months. Some dogs remain outwardly comfortable in the early weeks, whilst others may show a more rapid decline in energy, appetite, or body condition. The pace can differ markedly between individuals, influenced by factors that are not always apparent at the time of diagnosis.
Signals & patterns
Early signals
Firm swellings under the jaw
The submandibular lymph nodes, which sit beneath the lower jaw on either side, may become noticeably enlarged. The swellings are typically firm, smooth, and painless to the touch, so the dog often shows no discomfort when the area is examined.
Lumps in front of the shoulders
The prescapular nodes, located just in front of the shoulder blades, can become palpable as distinct lumps beneath the skin. Owners sometimes notice these when stroking or grooming, particularly in short-coated breeds where the contours are easier to feel.
Reduced appetite or selective eating
Some dogs begin to turn away from meals or eat less enthusiastically than usual, without any obvious sign of nausea or distress. The change can be subtle at first, sometimes attributed to weather, routine, or simply a mood shift.
Quieter energy levels
A dog may seem less inclined to initiate play, may lag slightly on walks, or may choose to rest more often during the day. The shift is often gradual, which can make it difficult to pinpoint when it began.
Weight loss despite stable routine
Body condition may decline even when diet and activity have not changed. The loss tends to be slow and can be masked by a thick coat or by the owner's daily familiarity with the dog's shape.
Later signals
Swelling behind the knees
The popliteal nodes, situated in the hollow behind the hind legs, may enlarge as more lymphoid tissue becomes involved. These nodes are often easier to feel than to see, particularly in dogs with heavier build or longer fur.
Breathing changes or cough
If lymph nodes within the chest become enlarged, they may press against airways or interfere with normal lung expansion. This can lead to a persistent cough, faster breathing, or reluctance to settle comfortably when lying down.
Digestive signs
In some dogs, lymphoid tissue within the gastrointestinal tract becomes involved, leading to vomiting, diarrhoea, or a more profound reluctance to eat. These signs can emerge later in the course or may occasionally be the first indication that something has shifted.
General malaise or withdrawal
A dog may become less interactive, seek out quiet corners, or show less interest in household activity. The shift in demeanour can be subtle and is sometimes mistaken for ageing or mood, rather than a signal of underlying change.
Click to read about the biological mechanisms
How this is usually investigated
Options & trade-offs
Related conditions
Lymphoma in Cats
Lymphoma in cats shares the same underlying process—uncontrolled multiplication of lymphocytes—but tends to present with different patterns of distribution and organ involvement. Understanding the differences in how this condition behaves across species can help contextualise the range of ways lymphoma may appear.
Cutaneous Lymphoma
Cutaneous lymphoma arises from the same cell type—lymphocytes—but remains localised to the skin rather than involving the lymph nodes throughout the body. Some dogs may develop skin involvement alongside or after multicentric disease, and the two forms can occasionally be seen in the same animal over time.
Splenic Lymphoma
Splenic lymphoma represents lymphoma that primarily affects the spleen, an organ rich in lymphatic tissue. In multicentric disease, the spleen may also be involved, and distinguishing where the disease began or which organs are most affected can shape the picture that emerges during investigation.
Hemangiosarcoma
Haemangiosarcoma is another cancer that can cause generalised illness and internal organ involvement in dogs, and the two conditions may occasionally be considered alongside one another when investigating unexplained weight loss, lethargy, or internal masses. The biological behaviour and cells of origin differ, but both can present with overlapping signs early on.
Canine Parvovirus
Canine parvovirus can cause severe suppression of the immune system and changes in white blood cell populations, and dogs undergoing chemotherapy for lymphoma may be at heightened risk of infection if exposed. The connection is one of vulnerability rather than shared cause, but both conditions involve significant changes in immune cell populations.
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