Mastocytoma
Encyclopedia
A mastocytoma or mast cell tumor
is a type of tumor
consisting of mast cell
s. It is found in humans and many animal species; in human medicine it also can refer to an accumulation or nodule
of mast cell
s that resembles a tumor.
Mast cells originate from the bone marrow
and are normally found throughout the connective tissue
of the body as normal components of the immune system
. As they release histamine
, they are associated with allergic reaction
s. Mast cells also respond to tissue trauma
. Mast cell granule
s contain histamine, heparin
, platelet-activating factor
, and other substances. Disseminated mastocytosis
is rarely seen in young dogs and cats, while mast cell tumors are usually skin tumors in older dogs and cats. Although not always malignant, they do have the potential to be. Up to 25 percent of skin tumors in dogs are mast cell tumors, with a similar number in cats.
-like nodule to a soft subcutaneous lump (similar on palpation to a benign lipoma
) to an ulcerated skin mass. All lumps should be checked by fine needle aspiration
; palpation or visual inspection is never adequate. Most mast cell tumors are small, raised lumps on the skin. They may be hairless, ulcerated, or itchy. They are usually solitary, but in about six percent of cases, there are multiple mast cell tumors (especially in Boxers and Pugs).
Manipulation of the tumor may result in redness and swelling from release of mast cell granules, also known as Darier's sign
, and prolonged local hemorrhage. In rare cases, a highly malignant tumor is present, and signs may include loss of appetite, vomiting
, diarrhea
, and anemia
. The presence of these signs usually indicates mastocytosis
, which is the spread of mast cells throughout the body. Release of a large amount of histamine at one time can result in ulceration of the stomach
and duodenum
(present in up to 25 percent of cases) or disseminated intravascular coagulation
. When metastasis
does occur, it is usually to the liver
, spleen
, lymph node
s and bone marrow
.
A needle aspiration biopsy
of the tumor will typically show a large number of mast cells. This is sufficient to make the diagnosis of a mast cell tumor, although poorly differentiated
mast cells may have few granules and thus are difficult to identify. The granules of the mast cell stain blue to dark purple with a Romanowsky stain
, and the cells are medium sized. However, a surgical biopsy
is required to find the grade
of the tumor. The grade depends on how well the mast cells are differentiated, mitotic
activity, location within the skin, invasiveness, and the presence of inflammation
or necrosis
.
However, there is a significant amount of discordance between veterinary pathologists in assigning grades to mast cell tumors due to imprecise criteria.
The disease is also staged according to the WHO
system:
X-ray
s, ultrasound
, or lymph node, bone marrow, or organ biopsies may be necessary to stage the disease.
s, such as diphenhydramine
, are given prior to surgery to protect against the effects of histamine released from the tumor. Wide margins (two to three centimeters) are required because of the tendency for the tumor cells to be spread out around the tumor. If complete removal is not possible due to the size or location, additional treatment, such as radiation therapy
or chemotherapy
, may be necessary. Prednisone
is often used to shrink the remaining tumor portion. H2 blockers, such as cimetidine
, protect against stomach damage from histamine. Vinblastine
and CCNU
are common chemotherapy agents used to treat mast cell tumors.
Toceranib
, a receptor tyrosine kinase
inhibitor, is used in the treatment of canine mast cell
tumors. It was recently approved by the U.S. Food and Drug Administration (FDA) as a dog-specific anticancer
drug.
Grade I or II mast cell tumors that can be completely removed have a good prognosis
. One study showed about 23 percent of incompletely removed grade II tumors recurred locally. Any mast cell tumor found in the gastrointestinal tract
, paw, or on the muzzle has a guarded prognosis. Previous beliefs that tumors in the groin or perineum
carried a worse prognosis have been discounted. Tumors that have spread to the lymph nodes or other parts of the body have a poor prognosis. Any dog showing symptoms of mastocytosis or with a grade III tumor has a poor prognosis. Dogs of the Boxer breed have a better than average prognosis because of the relatively benign behavior of their mast cell tumors. Multiple tumors that are treated similarly to solitary tumors do not seem to have a worse prognosis.
Mast cell tumors do not necessarily follow the histological prognosis. Further prognostic information can be provided by AgNOR stain of histological or cytological specimen. Even then, there is a risk of unpredictable behavior.
type that appears as subcutaneous nodules and may resolve spontaneously. Young Siamese cat
s are at an increased risk for the histiocytic type, although the mast cell type is the most common in all cats and is considered to be benign when confined to the skin.
Mast cell tumors of the skin are usually located on the head or trunk. Gastrointestinal and splenic
involvement is more common in cats than in dogs; 50 percent of cases in cats primarily involved the spleen or intestines. Gastrointestinal mast cell tumors are most commonly found in the muscularis layer
of the small intestine
, but can also be found in the large intestine
. It is the third most common intestinal tumor in cats, after lymphoma
and adenocarcinoma
.
Diagnosis and treatment are similar to that of the dog. Cases involving difficult to remove or multiple tumors have responded well to strontium-90
radiotherapy
as an alternative to surgery. The prognosis for solitary skin tumors is good, but guarded for tumors in other organs. Histological grading of tumors has little bearing on prognosis.
s. They usually occur as benign, solitary masses on the skin of the head, neck, trunks, and legs. Mineralization of the tumor is common. In pig
s and cattle
, mast cell tumors are rare. They tend to be solitary and benign in pigs and multiple and malignant in cattle. Mast cell tumors are found in the skin of cattle most commonly, but these may be metastases from tumors of the viscera
. Other sites in cattle include the spleen, muscle, gastrointestinal tract, omentum
, and uterus.
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
is a type of tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
consisting of mast cell
Mast cell
A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin...
s. It is found in humans and many animal species; in human medicine it also can refer to an accumulation or nodule
Nodule (medicine)
For use of the term nodule in dermatology, see Nodule In medicine, a nodule refers to a relatively hard, roughly spherical abnormal structure....
of mast cell
Mast cell
A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin...
s that resembles a tumor.
Mast cells originate from the bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
and are normally found throughout the connective tissue
Connective tissue
"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...
of the body as normal components of the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
. As they release histamine
Histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...
, they are associated with allergic reaction
Allergy
An Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
s. Mast cells also respond to tissue trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
. Mast cell granule
Granule
Granule is a generic term used for a small particle or grain. The generic term is employed in a variety of specific contexts.* Granule , visible structures in the photosphere of the Sun arising from activity in the Sun's convective zone...
s contain histamine, heparin
Heparin
Heparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...
, platelet-activating factor
Platelet-activating factor
Platelet-activating factor, also known as a PAF, PAF-acether or AGEPC is a potent phospholipid activator and mediator of many leukocyte functions, including platelet aggregation and degranulation, inflammation, and anaphylaxis...
, and other substances. Disseminated mastocytosis
Mastocytosis
Mastocytosis is a group of rare disorders of both children and adults caused by the presence of too many mast cells and CD34+ mast cell precursors in a person's body.- Classification :Mastocytosis can occur in a variety of forms:...
is rarely seen in young dogs and cats, while mast cell tumors are usually skin tumors in older dogs and cats. Although not always malignant, they do have the potential to be. Up to 25 percent of skin tumors in dogs are mast cell tumors, with a similar number in cats.
Signs
Mast cell tumors are known among veterinary oncologists as 'the great pretenders' because their appearance can be varied, from a wartWart
A wart is generally a small, rough growth, typically on a human’s hands or feet but often other locations, that can resemble a cauliflower or a solid blister. They are caused by a viral infection, specifically by human papillomavirus 2 and 7. There are as many as 10 varieties of warts, the most...
-like nodule to a soft subcutaneous lump (similar on palpation to a benign lipoma
Lipoma
A lipoma is a benign tumor composed of adipose tissue. It is the most common form of soft tissue tumor. Lipomas are soft to the touch, usually movable, and are generally painless. Many lipomas are small but can enlarge to sizes greater than six centimeters. Lipomas are commonly found in adults...
) to an ulcerated skin mass. All lumps should be checked by fine needle aspiration
Needle aspiration biopsy
Needle aspiration biopsy , may refer to fine needle aspiration cytology , fine needle aspiration biopsy and fine needle aspiration , is a diagnostic procedure sometimes used to investigate superficial lumps or masses...
; palpation or visual inspection is never adequate. Most mast cell tumors are small, raised lumps on the skin. They may be hairless, ulcerated, or itchy. They are usually solitary, but in about six percent of cases, there are multiple mast cell tumors (especially in Boxers and Pugs).
Manipulation of the tumor may result in redness and swelling from release of mast cell granules, also known as Darier's sign
Darier's sign
Darier's sign is a change observed after stroking the skin of a person with systemic mastocytosis or urticaria pigmentosa.In general, the skin becomes swollen, itchy and red. This is a result of compression of mast cells, which are hyperactive in these diseases. These mast cells release...
, and prolonged local hemorrhage. In rare cases, a highly malignant tumor is present, and signs may include loss of appetite, vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, and anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
. The presence of these signs usually indicates mastocytosis
Mastocytosis
Mastocytosis is a group of rare disorders of both children and adults caused by the presence of too many mast cells and CD34+ mast cell precursors in a person's body.- Classification :Mastocytosis can occur in a variety of forms:...
, which is the spread of mast cells throughout the body. Release of a large amount of histamine at one time can result in ulceration of the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
and duodenum
Duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum...
(present in up to 25 percent of cases) or disseminated intravascular coagulation
Disseminated intravascular coagulation
Disseminated intravascular coagulation , also known as disseminated intravascular coagulopathy or consumptive coagulopathy, is a pathological activation of coagulation mechanisms that happens in response to a variety of diseases. DIC leads to the formation of small blood clots inside the blood...
. When metastasis
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
does occur, it is usually to the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
, spleen
Spleen
The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...
, lymph node
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s and bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
.
Diagnosis
Needle aspiration biopsy
Needle aspiration biopsy , may refer to fine needle aspiration cytology , fine needle aspiration biopsy and fine needle aspiration , is a diagnostic procedure sometimes used to investigate superficial lumps or masses...
of the tumor will typically show a large number of mast cells. This is sufficient to make the diagnosis of a mast cell tumor, although poorly differentiated
Cellular differentiation
In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...
mast cells may have few granules and thus are difficult to identify. The granules of the mast cell stain blue to dark purple with a Romanowsky stain
Romanowsky stain
Romanowsky staining is a prototypical staining technique that was the forerunner of several distinct but similar methods, including Giemsa, Jenner, Wright, Field, and Leishman stains, which are used to differentiate cells in pathologic specimens....
, and the cells are medium sized. However, a surgical biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
is required to find the grade
Grading (tumors)
In pathology, grading is a measure of the cell appearance in tumors and other neoplasms. Some pathology grading systems apply only to malignant neoplasms ; others apply also to benign neoplasms. The neoplastic grading is a measure of cell anaplasia in the sampled tumors arising from the...
of the tumor. The grade depends on how well the mast cells are differentiated, mitotic
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...
activity, location within the skin, invasiveness, and the presence of inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
or necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
.
- Grade I - well differentiated and mature cells with a low potential for metastasis
- Grade II - intermediately differentiated cells with potential for local invasion and moderate metastatic behavior
- Grade III - undifferentiated, immature cells with a high potential for metastasis
However, there is a significant amount of discordance between veterinary pathologists in assigning grades to mast cell tumors due to imprecise criteria.
The disease is also staged according to the WHO
Who
Who may refer to:* Who , an English-language pronoun* who , a Unix command* Who?, one of the Five Ws in journalism- Art and entertainment :* Who? , a 1958 novel by Algis Budrys...
system:
- Stage I - a single skin tumor with no spread to lymph nodeLymph nodeA lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s - Stage II - a single skin tumor with spread to lymph nodes in the surrounding area
- Stage III - multiple skin tumors or a large tumor invading deep to the skin with or without lymph node involvement
- Stage IV - a tumor with metastasis to the spleen, liver, bone marrow, or with the presence of mast cells in the blood
X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
s, ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
, or lymph node, bone marrow, or organ biopsies may be necessary to stage the disease.
Treatment and prognosis
Removal of the mast cell tumor through surgery is the treatment of choice. AntihistamineAntihistamine
An H1 antagonist is a histamine antagonist of the H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions...
s, such as diphenhydramine
Diphenhydramine
Diphenhydramine hydrochloride is a first-generation antihistamine possessing anticholinergic, antitussive, antiemetic, and sedative properties which is mainly used to treat allergies. Like most other first-generation antihistamines, the drug also has a powerful hypnotic effect, and for this reason...
, are given prior to surgery to protect against the effects of histamine released from the tumor. Wide margins (two to three centimeters) are required because of the tendency for the tumor cells to be spread out around the tumor. If complete removal is not possible due to the size or location, additional treatment, such as radiation therapy
Radiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
or chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
, may be necessary. Prednisone
Prednisone
Prednisone is a synthetic corticosteroid drug that is particularly effective as an immunosuppressant drug. It is used to treat certain inflammatory diseases and some types of cancer, but has significant adverse effects...
is often used to shrink the remaining tumor portion. H2 blockers, such as cimetidine
Cimetidine
Cimetidine INN is a histamine H2-receptor antagonist that inhibits the production of acid in the stomach. It is largely used in the treatment of heartburn and peptic ulcers. It is marketed by GlaxoSmithKline under the trade name Tagamet...
, protect against stomach damage from histamine. Vinblastine
Vinblastine
Vinblastine is an antimicrotubule drug used to treat certain kinds of cancer, including Hodgkin's lymphoma, non-small cell lung cancer, breast cancer, head and neck cancer, and testicular cancer. It is also used to treat Langerhan cell histiocytosis....
and CCNU
Lomustine
Lomustine is an alkylating nitrosourea compound used in chemotherapy. It is in the same family as streptozotocin. This is a highly lipid soluble drug, and thus crosses the blood brain barrier. This property makes it ideal for treating brain tumors, and is its primary use...
are common chemotherapy agents used to treat mast cell tumors.
Toceranib
Toceranib
Toceranib is a receptor tyrosine kinase inhibitor and is used in the treatment of canine mast cell tumor also called mastocytoma. Together with masitinib , Toceranib is the only dog-specific anti-cancer drug approved by the U.S. Food and Drug Administration. It is marketed as Palladia as its...
, a receptor tyrosine kinase
Receptor tyrosine kinase
Receptor tyrosine kinases s are the high-affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones. Of the 90 unique tyrosine kinase genes identified in the human genome, 58 encode receptor tyrosine kinase proteins....
inhibitor, is used in the treatment of canine mast cell
Mast cell
A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin...
tumors. It was recently approved by the U.S. Food and Drug Administration (FDA) as a dog-specific anticancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
drug.
Grade I or II mast cell tumors that can be completely removed have a good prognosis
Prognosis
Prognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...
. One study showed about 23 percent of incompletely removed grade II tumors recurred locally. Any mast cell tumor found in the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
, paw, or on the muzzle has a guarded prognosis. Previous beliefs that tumors in the groin or perineum
Perineum
In human anatomy, the perineum is a region of the body including the perineal body and surrounding structures...
carried a worse prognosis have been discounted. Tumors that have spread to the lymph nodes or other parts of the body have a poor prognosis. Any dog showing symptoms of mastocytosis or with a grade III tumor has a poor prognosis. Dogs of the Boxer breed have a better than average prognosis because of the relatively benign behavior of their mast cell tumors. Multiple tumors that are treated similarly to solitary tumors do not seem to have a worse prognosis.
Mast cell tumors do not necessarily follow the histological prognosis. Further prognostic information can be provided by AgNOR stain of histological or cytological specimen. Even then, there is a risk of unpredictable behavior.
Dogs
Mast cell tumors mainly occur in older adult dogs, but have been known to occur on rare occasions in puppies. The following breeds are commonly affected by mast cell tumors:- BoxerBoxer (dog)Developed in Germany, the Boxer is a breed of stocky, medium-sized, short-haired dog. The coat is smooth and fawn or brindled, with or without white markings. Boxers are brachycephalic , and have a square muzzle, mandibular prognathism , very strong jaws and a powerful bite ideal for hanging on to...
- Staffordshire bull terrierStaffordshire Bull TerrierThe Staffordshire Bull Terrier is a medium-sized, short-coated, old-time breed of dog. It is an English dog, where it is the 5th most popular breed, and related to the bull terrier...
- BulldogBulldogBulldog is the name for a breed of dog commonly referred to as the English Bulldog. Other Bulldog breeds include the American Bulldog, Olde English Bulldogge and the French Bulldog. The Bulldog is a muscular heavy dog with a wrinkled face and a distinctive pushed-in nose...
- Basset houndBasset HoundThe Basset Hound is a short-legged breed of dog of the hound family. They are scent hounds, bred to hunt rabbits and hare by scent. Their sense of smell for tracking is second only to that of the Bloodhound....
- WeimaranerWeimaranerThe Weimaraner is a dog that was originally bred for hunting in the early 19th century. Early Weimaraners were used by royalty for hunting large game such as boar, bear, and deer. As the popularity of large game hunting began to decline, Weimaraners were used for hunting smaller animals like...
- Boston terrierBoston TerrierThe Boston Terrier is a breed of dog originating in the United States of America. This "American Gentleman" was accepted in 1893 by the American Kennel Club as a non-sporting breed. Color and markings are important when distinguishing this breed to the AKC standard. They should be either black,...
- Golden retrieverGolden RetrieverThe Golden Retriever is a medium-sized breed of dog. They were historically developed as gundogs to retrieve shot waterfowl such as ducks and upland game birds during hunting and shooting parties. As such, they were bred to have a soft mouth to retrieve game undamaged and have an instinctive love...
- Labrador retrieverLabrador RetrieverThe Labrador Retriever is one of several kinds of retriever, a type of gun dog. A breed characteristic is webbed paws for swimming, useful for the breed's original purpose of retrieving fishing nets. The Labrador is the most popular breed of dog by registered ownership in Canada, the United...
- BeagleBeagleThe Beagle is a breed of small to medium-sized dog. A member of the Hound Group, it is similar in appearance to the Foxhound, but smaller, with shorter legs and longer, softer ears. Beagles are scent hounds, developed primarily for tracking hare, rabbit, and other game...
- German shorthaired pointerGerman Shorthaired PointerThe German shorthaired pointer is a breed of dog developed in the 19th century in Germany for hunting.The breed is streamlined yet powerful with strong legs that make it able to move rapidly and turn quickly. It has moderately long floppy ears set high on the head. Its muzzle is long, broad, and...
- Scottish terrierScottish TerrierThe Scottish Terrier , popularly called the Scottie, is a breed of dog. Initially one of the highland breeds of Terrier that were grouped under the name of Skye Terrier, it is one of five breeds of terrier that originated in Scotland, the other four being the modern Skye, Cairn, Dandie Dinmont, and...
- PugPugThe pug is a "toy" breed of dog with a wrinkly, short-muzzled face, and curled tail. The breed has a fine, glossy coat that comes in a variety of colors, and a compact square body with well-developed muscle. They have been described as multum in parvo , referring to the pug's personality and...
- Shar peiShar PeiThe Shar Pei, or Chinese Shar-Pei, is a breed of dog known for its distinctive features of deep wrinkles and a blue-black tongue. The breed comes from China. The name translates to "sand skin" and refers to the texture of its short, rough coat...
- Rhodesian ridgebackRhodesian RidgebackThe Rhodesian Ridgeback is a dog breed developed in Southern Africa, where it was used to hunt Lions. This is most likely why this dog is known for its bravery...
Cats
Two types of mast cell tumors have been identified in cats, a mast cell type similar to dogs and a histiocyticHistiocyte
A histiocyte is a cell that is part of the mononuclear phagocyte system . The mononuclear phagocytic system is part of the organism's immune system...
type that appears as subcutaneous nodules and may resolve spontaneously. Young Siamese cat
Siamese (cat)
The Siamese is one of the first distinctly recognized breeds of Oriental cat. The origins of the breed are unknown, but it is believed to be from Thailand. In Thailand, where they are one of several native breeds, they are called Wichian Mat...
s are at an increased risk for the histiocytic type, although the mast cell type is the most common in all cats and is considered to be benign when confined to the skin.
Mast cell tumors of the skin are usually located on the head or trunk. Gastrointestinal and splenic
Spleen
The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...
involvement is more common in cats than in dogs; 50 percent of cases in cats primarily involved the spleen or intestines. Gastrointestinal mast cell tumors are most commonly found in the muscularis layer
Muscularis mucosae
The lamina muscularis mucosae is the thin layer of smooth muscle found in most parts of the gastrointestinal tract, located outside the lamina propria mucosae and separating it from the submucosa....
of the small intestine
Small intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
, but can also be found in the large intestine
Large intestine
The large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...
. It is the third most common intestinal tumor in cats, after lymphoma
Lymphoma in animals
Lymphoma in animals is a type of cancer defined by a proliferation of malignant lymphocytes within solid organs such as the lymph nodes, bone marrow, liver and spleen. The disease also may occur in the eye, skin, and gastrointestinal tract. It is also known as lymphosarcoma.-Lymphoma in...
and adenocarcinoma
Adenocarcinoma
Adenocarcinoma is a cancer of an epithelium that originates in glandular tissue. Epithelial tissue includes, but is not limited to, the surface layer of skin, glands and a variety of other tissue that lines the cavities and organs of the body. Epithelium can be derived embryologically from...
.
Diagnosis and treatment are similar to that of the dog. Cases involving difficult to remove or multiple tumors have responded well to strontium-90
Strontium-90
Strontium-90 is a radioactive isotope of strontium, with a half-life of 28.8 years.-Radioactivity:Natural strontium is nonradioactive and nontoxic, but 90Sr is a radioactivity hazard...
radiotherapy
Radiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
as an alternative to surgery. The prognosis for solitary skin tumors is good, but guarded for tumors in other organs. Histological grading of tumors has little bearing on prognosis.
Other animals
Mast cell tumors are an uncommon occurrence in horseHorse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s. They usually occur as benign, solitary masses on the skin of the head, neck, trunks, and legs. Mineralization of the tumor is common. In pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...
s and cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
, mast cell tumors are rare. They tend to be solitary and benign in pigs and multiple and malignant in cattle. Mast cell tumors are found in the skin of cattle most commonly, but these may be metastases from tumors of the viscera
Viscus
In anatomy, a viscus is an internal organ, and viscera is the plural form. The viscera, when removed from a butchered animal, are known collectively as offal...
. Other sites in cattle include the spleen, muscle, gastrointestinal tract, omentum
Omentum
Omentum may refer to:* greater omentum* lesser omentum...
, and uterus.