Common in dogs, apparently rare in humans, my dog Zippie (around 13.5 years old) lived with this condition and not until after I put her to sleep (having a really aggressive mast cell sarcoma did I understand all those behavioral (odd, and troublesome) issues that she delt so well with.
In general it is thought that tumors composed of mast cells, which are a type of blood cell. Mast cells (with other white cells) are involved in innate immunity, and influence the immune (inflammatory) response of the body to foreign proteins (allergens). ,Increased mast cells (mastocytosis) affects blood forming cells of the body, that includes spleen, liver, gastrointestinal tract, and bone marrow, but also can appear as dermal tumors just under the epidermis, as mast cell sarcomas.
Quotes from the internet:
“These tumors share a universally bad prognosis with survival times of less than 4 months. They behave aggressively and require more aggressive therapy. These tumors overall showed a median survival time of greater than 2 years but there were some tumors that behaved aggressively despite their low grade.
Can dogs recover from mast cell tumor?
Well-differentiated mast cell tumors in the skin often can be treated successfully by aggressive surgery. High grade tumors are associated with aggressive tumor behavior, and most dogs die within 4 to 6 months after surgery as a result of metastasis and tumor degranulation.”
“Mastocytosis develops when mast cells increase in number and accumulate in tissues over a period of years. Mast cells are part of the immune system and are normally present in many body tissues, particularly the skin, lungs, and lining of the intestine. Mast cells produce histamine, a substance involved in inflammatory and allergic reactions and in the production of stomach acid. Because the number of mast cells increases, levels of histamine increase. Histamine can cause many symptoms, including digestive problems.”
“Cutaneous mastocytosis usually occurs in children. Occasionally, mast cells accumulate only as a single mass in the skin (mastocytoma), typically before age 6 months. More commonly, mast cells congregate in many areas of the skin, forming small reddish brown spots or bumps (called urticaria pigmentosa). Urticaria pigmentosa rarely progresses to systemic mastocytosis in children but may do so more often in adults.”
Systemic mastocytosis usually occurs in adults. Typically, mast cells accumulate in bone marrow (where blood cells are produced). Often, they also accumulate in the skin, stomach, intestine, liver, spleen, and lymph nodes. Organs may continue to function, with little disruption. But if many mast cells accumulate in the bone marrow, too few blood cells are produced, and serious blood disorders, such as leukemia, can develop. If many mast cells accumulate in organs, the organs malfunction. The resulting problems can be life threatening.”
In Zippies case, I think she had systemic disease (mastocytosis) and that seeded a mast cell tumor in her lower leg, and ultimately a large aggressive mast cell sarcoma on her outer thigh.
Quote – “affect dogs of any age but typically affect middle-aged to older dogs” (from Laura D Garrett). Clinically, heavy reliance is placed on the MI for behavior prediction (from Laura D Garrett). “The subjectivity and variability between pathologists bring into question the heavy reliance placed on the grade of an MCT to predict its behavior (from Laura D Garrett).
Qutoe “Mast cells and basophils as effectors of the allergic response” (http://what-when-how.com/acp-medicine/allergic-response-part-2/). If a release of granules from a mast cell takes less than 60 seconds, then a trigger can be seen almost immediately. Mature mast cells in peripheral tissues may reside there for many months, retaining antigen-specific IgE for periods that exceed the lifespan of IgE in the circulation. Mast cells are strategically distributed in tissues or at mucosal surfaces that interface with the external environment; they are also in proximity to blood vessels and nerves (see prior link).
Flushing is common. may develop because too much histamine is produced, stimulating secretion of excess stomach acid. Ulcers can cause stomach pain. Nausea, vomiting, and chronic diarrhea may also occur.
First line of this commentary on mast cell disease is going to include my sadness, and also a sincere amusement at the places grief can be trigggered: In the canned tuna aisle in the grocery store, and the relationship will become clear.
I found Zippie running lose near the tennis court behind North Avondale Montessori School. I remember seeing two little boys and they were intrigued with the dog and I lent them my leash (from a current rescue Zodie who was at the tennis court with me) to take the dog and ask their mother if they could keep her. (obvious result was the mom said no, and they brought the puppy back to me). We went to the vet for shots, and exam, and her approximate age was 3 months, and that date was Sept 16, 2009. Then we just began the process of getting her adjusted to the dog I already had.
There were not really any health issues with Zippie that would have suggested that she had a mast cell issue when she was young, though there were obvious signs that she had an immune system that didnt function very well: ear infections, diarrhea, urinary tract infections. I took the number of incidences as just a little worse than normal, not really that troublesome.
Her energy level and interest in walking and playing was pretty normal.
Middle age began to show serious food allergies, and symptoms of mastocytosis, and this was before any subcuteous tumors were present.
Oakley Sq Annimal Hospital removed a subcutaneous lump from the front of Zipper’s leg on Aug 3, 2020. This tumor (skin and tumor were movable on the underlying tissue, and dense, and waiting to remove the tumor would have resulted in not being able to find skin to close the incision. I dont know whether an adequate margin around this tumor was possible. This is just over the predicted survival time after a mast cell tumor has been removed, she lived from that surgery until Feb 3, 2023, so just over two years. The last two weeks saw tremendously rapid tumor grown and increasing evidence of mast cell degranulation (in terms of shivering, panting behavior).
References:
Thank you to the authors of the following articles