Most people think of cancer as a disease that affects middle-aged to older dogs, but this is unfortunately not always the case. Puppies as young as 18 weeks of age have been diagnosed with tumors of various types. In fact certain tumors are more likely to occur in young animals rather than adult dogs.
Lymphoma or Lymphosarcoma
Lymphoma is a cancer of the immune system that affects a type of white blood cell called the lymphocyte. Although lymphoma is typically diagnosed in dogs age 6 years and up, it has been reported in puppies as young as 9 months of age in a case report by veterinary ophthalmologists N Escanilla et al in 2012. Any breed can be affected by lymphoma, but Golden retrievers, boxers and Scottish terriers are at higher risk of developing lymphoma than other breeds. Lymphoma can affect the entire body, so symptoms of the disease are highly variable but can include external lymph nodes enlargement, lack of energy, loss of appetite, vomiting or diarrhea.
If your dog is exhibiting signs of illness or you notice a new swelling, seek veterinary care. Needle aspiration of lymph nodes is a common tool used to diagnose lymphoma. If lymphoma is confirmed, the recommended treatment plan is chemotherapy. Unfortunately lymphoma is rarely cured with treatment, but your veterinarian can discuss the specifics of your dog's case and define a more accurate prognosis.
The Pet Health Library has a helpful diagram that identifies the location of external lymph nodes in dogs.
Mast cell tumors and histiocytomas are the skin tumors most commonly diagnosed in young dogs. Histiocytomas often appear on the skin as pink, raised and often hairless masses and are almost always found in dogs younger than 2 to 3 years old. They can be diagnosed with either needle aspiration or biopsy. Although surgical removal is a good method of treatment, many of these tumors spontaneously will regress over time and therefore surgery may not be necessary. Your veterinarian can guide you on the best method of treatment. Histiocytomas are considered benign tumors and are not expected to spread to other locations, so the prognosis is good for a dog diagnosed with this tumor type.
Mast cell tumors can have a similar appearance to histiocytomas, so it is important to have your veterinarian differentiate between them. Needle aspiration is a reliable way to diagnose mast cell tumors. Unlike histiocytomas, mast cell tumors will not spontaneously regress and therefore surgical removal will be required for treatment. Some mast cell tumors will spread to other locations in the body, so the prognosis may be more guarded for dogs diagnosed with this disease. The biopsy report obtained after surgery will give your veterinarian information that will help predict your dog's prognosis.
Osteosarcomas of Bone
Osteosarcomas are tumors of bone that most commonly occur in dogs 6 years or older. However, there is a small population of dogs diagnosed with osteosarcoma between 18 and 24 months of age. Large and giant-breed dogs such as Great Danes and Rottweilers are most at risk of developing this cancer. The most common symptom is limping on a particular leg due to pain. X-rays of the leg often show a lesion in the bone and the tumor is usually diagnosed with biopsy.
The prognosis for osteosarcoma tends to be guarded because the tumor frequently spreads to the lungs or other bones, even after removal. However, treatment can result in prolonged survival in many cases. Discuss your dog's case with your veterinarian to make the best decision possible for you and your dog.
Don't rule out cancer as a possible diagnosis just because your dog is young. Visit your veterinarian if you find any masses or swellings or your dog is exhibiting abnormal symptoms.