When your dog is diagnosed with one of the rarest kinds of lymphoma how do you know where to start on finding information? Your vet is happy to provide what they know on the topic, but otherwise, you’re left sifting through the information out there on the internet… Luckily, you’ve found this blog. We want to help you understand exactly what a cutaneous lymphoma diagnosis means for your pup.
All lymphomas impact the lymphocytes, which are cells that help the body's immune system to fight off any pathogens. Lymphocytes are all over the body, but they have 'check-in' points in the lymph nodes. It is in those lymph nodes that most cases of lymphoma develop.1
However, cutaneous lymphoma is an extranodal lymphoma, which means that it develops on the outside of the lymph nodes. Specifically, cutaneous develops in the lymphocytes on the skin. This makes it very different from the more common multi-centric lymphoma. Cutaneous lymphoma represents 5% of all the canine lymphomas.2
Cutaneous lymphoma develops when cells around the hair follicles and sweat glands develop malignant cells, causing the lymphocytes to change into cancerous cells. These cancerous cells in turn will create changes on the skin in the form of either nodules (red, button-like lumps), plaques (large, flat raised skin), or other lesions. The issue with cutaneous lymphoma, as with all cancers, is when it spreads to other parts of the body, including the lymph nodes, bloodstream, and abdominal organs.3
Cutaneous lymphoma is by nature a T-cell lymphoma type, which typically means that it is more aggressive and faster to advance. There are two main subgroups of cutaneous lymphomas, epitheliotropic and non-epitheliotropic, we are going to focus on epitheliotropic because it is more common in the already rare subgroup of skin based lymphomas. The cause of canine epitheliotropic lymphoma is unclear.4
Because cutaneous lymphoma is a skin cancer, the first sign a pet parent will likely encounter will be a lesion of some kind on the skin. Dogs developing this malignancy usually had a recent history of chronic dermatitis. There are several different kinds of lesions that can indicate the development of cutaneous lymphoma and they can appear anywhere on the body. Types of lesions can be ulcerated in infected patches, nodules, plaques, and scabs. Some of the common locations for these to develop are on the oral mucosa, mucocutaneous junctions (lips, nose, and eyelids) and the gums. Other organs are affected in the later stages of the disease.
Depending on the stage that the cutaneous lymphoma is in when it is found, symptoms can be as simple as an itchy location on the body, or signs of discomfort while eating if the lesion is on or in the mouth. Or the symptoms can be more systemic signs of unwellness, like lethargy, vomiting or diarrhea, or increased urination and thirst.
Any time that a pet parent finds an unknown lump, bump, or lesion on their pet’s skin, they should address it with their vet to make sure that nothing is wrong. A majority of these cases will be addressed in the same manner.
If there are no signs of systemic illness, the vet will take a sample of the lesion to test in a skin biopsy. A skin biopsy is performed by providing some anesthetic, local or general depending on the patient, and removing a small portion of the affected skin to be examined under a microscope by a pathologist. The pathologist is a specialist who will look for signs of malignant cells in the sample and be able to tell if the growth or lesion is cancerous.
Some patients will have the option for another biopsy performed through a fine needle aspirate (FNA), this is done if there are signs that the lymph nodes have been affected or if there is a nodule that the vet is able to pull cells from.3
Differentiation of epitheliotropic lymphoma from non-neoplastic dermatitis can be challenging in the early stages of the disease. Molecular testing by PCR and detection of lymphocyte-specific antigen markers by flow cytometry aid in characterizing the cancer and providing a definitive diagnosis.5
There are a few options of potential treatments for patients with canine cutaneous lymphoma, though unfortunately, due to its rareness, there has not been much research into learning what is the most effective of these treatments.
In general, t most common treatment option for dogs with lymphoma is chemotherapy, however, for dogs with cutaneous lymphoma, there is potential for some other treatment options. Because cutaneous lymphoma can be found before it spreads to other parts of the body, there is a possibility that external treatments like surgical removal or radiation therapy may be suggested.
For chemotherapy treatments, protocols that are recommended involve CCNU (lomustine) alone or in combinations with other other drugs. Some treatment protocols will provide an additional systemic treatment involving a vitamin A derivative to supplement surgery.3
Unfortunately, there is not a lot of conclusive research on the best treatment for cutaneous lymphoma cases because they are so rare and are the more aggressive, T-cell, type. The expected response to treatment is usually encouraging for a short period of time. For the dogs treated with CCNU, the response duration was reported to be approximately 3 months.
As with most cancers, there is potential for experimental treatments and new developments to arise as more studies are completed.
Unfortunately, cutaneous lymphoma does not have a great potential for positive outcomes. The overall survival in dogs diagnosed with epitheliotropic lymphoma is significantly shorter than those with non-epitheliotropic lymphoma. If found early and treated right away, the survival time for most patients is somewhere between 5-10 months. In rare instances, the cancer develops much more slowly within the patient's body, and those pets are able to live a fulfilling life for several more years rather than a few months. However, there is no way to know if patients would be predisposed to this slower development.
Dogs who undergo treatment for their cutaneous lymphoma will see a complete or partial response to the treatment, with a 50-100% improvement in their skin lesions. Those who have a complete response will typically see longer survival times. However, because lymphoma is not curable, there is always potential for the cancer to come back.6
ImpriMed uses state-of-the-art labs, a large database of dogs with lymphoma, and artificial intelligence to develop a Personalized Prediction Profile for your dog. It’s personalized because it will focus directly on how your pet’s live cancer cells will react to medication, not just what has worked for other patients in the past.
ImpriMed will help your vet choose the best possible chemotherapy treatment protocol that will have the most efficient results, without the trial and error that comes with the old method of choosing treatments.