Lymphoma is a common cancer in dogs, accounting for as many as twenty percent of all cancers, across all breeds and all ages.
A dog can be diagnosed with any of several subtypes of canine lymphoma, better referred to as lymphosarcoma or LSA. These subtypes typically have to do with the region of the dog's body that is affected—for instance, gastrointestinal LSA affects your dog's GI tract, which could mean the stomach, liver, intestines, and abdominal lymph nodes, while a cutaneous LSA would be found on the skin of your dog.
Treatments and prognoses vary for LSA, with one of the most important factors being when the LSA is discovered and when treatment begins.
Diligence is necessary to diagnose canine lymphoma. While the initial suspicion that something is wrong with your dog will come from you, the initial suspicion of LSA will usually come from your vet.
The most obvious symptom will be swollen lymph nodes, notably those that can be felt under the neck, in front of the shoulders, or behind the. However, the absence of swollen nodes in these areas does not exclude lymphoma. Not only are there lymph nodes that can't be felt, there are other ways of developing LSA as well as other symptoms, including:
Generally speaking, if your dog is symptomatic, he's not going to feel too well. However, don't leave the diagnosis of your dog to yourself; if you have any reason to think your dog is feeling unwell, see your vet immediately.