Skin cancer in cats and dogs
Encyclopedia
Many types of skin tumors, both benign
(noncancerous) and malignant
(cancerous), exist. Approximately 20-40% of primary skin tumors are malignant
in dogs and 50-65%
are malignant
in cats. Not all forms of skin cancer in cats and dogs are caused by sun exposure, but it can happen occasionally. On dogs, the nose and pads of the feet contain sensitive skin and no fur to protect from the sun. Also, cats and dogs with thin or light-colored coats are at a higher risk of sun damage over their entire bodies.
tumors in these cells, which do not metastasize. These tumors are found on areas of the body that has hair. Most malignant melanomas occur on the mouth or mucous membranes, but they are occasionally found on parts of the body covered with hair. They tend to grow extremely fast and are likely to spread to other organs, including the lungs and liver
.
The cause of melanomas remains unknown, although genetic factors seem to play a role. Additionally, trauma or compulsive licking of a particular spot on the skin may increase the likelihood that cells will multiply, thereby raising the chances that cells will mutate during the division process and become cancerous.
(FIV) has also been linked to the development of squamous cell carcinoma
in cats, although it is unclear what role the virus plays in the development of these tumors.
, are the most common skin tumors in canines. Mast cell
tumors are the second most common skin tumor in the cat, accounting approximately for 20% of all skin tumors. Veterinarians don’t know what causes mast cell tumors to develop, although there have been cases where they have been linked to inflammation or irritants on the skin. Evidence suggests genetic
factors are often important, and the hormones estrogen
and progesterone
may also affect cancer growth.
Basal cell tumors are most commonly seen in Siamese
and domestic longhaired cats. Rarely, basal cell tumors become malignant
. This occurs primarily in Persian cats.
tumors are slow growing and painless, with well defined boundaries and freely movable. In contrast, malignant tumors tend to be rapidly growing and often ulcerated with ill-defined boundaries.
Cats and dogs sometimes experience itchiness because of the cancer, which might cause them to scratch or chew at the affected area. This will often lead to redness of the skin or a flaky appearance.
and tissue biopsy
.
Cytology is an important tool that can help the veterinarian distinguish a tumor from inflammatory lesions. The biopsy
technique used will largely depend on the tumor's size and location. Small masses are usually completely excised and sent to the pathology
lab to confirm that the surrounding healthy tissues that were excised along with the tumor do not contain any cancer cells. If the tumor is larger, a small sample is removed for analysis and depending on the results, appropriate treatment is chosen. Depending on the tumor type and its level of aggressiveness, additional diagnostic tests can include blood tests to assess the pet’s overall health, chest X-rays to check for lung metastasis, and abdominal ultrasound
to check for metastasis
to other internal organs.
, chemotherapy
, or immunotherapy
exist.
When detected early, skin cancer in cats and dogs can often be treated successfully. In many cases, a biopsy
can remove the whole tumor, as long as the healthy tissues removed from just outside the tumor area do not contain any cancer cells.
Benign
A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...
(noncancerous) and malignant
Malignant
Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...
(cancerous), exist. Approximately 20-40% of primary skin tumors are malignant
Malignant
Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...
in dogs and 50-65%
are malignant
Malignant
Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...
in cats. Not all forms of skin cancer in cats and dogs are caused by sun exposure, but it can happen occasionally. On dogs, the nose and pads of the feet contain sensitive skin and no fur to protect from the sun. Also, cats and dogs with thin or light-colored coats are at a higher risk of sun damage over their entire bodies.
Malignant Melanoma
Malignant melanoma affects pigmented cells called melanocytes. Cats and dogs often develop benignBenign
A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...
tumors in these cells, which do not metastasize. These tumors are found on areas of the body that has hair. Most malignant melanomas occur on the mouth or mucous membranes, but they are occasionally found on parts of the body covered with hair. They tend to grow extremely fast and are likely to spread to other organs, including the lungs and 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...
.
The cause of melanomas remains unknown, although genetic factors seem to play a role. Additionally, trauma or compulsive licking of a particular spot on the skin may increase the likelihood that cells will multiply, thereby raising the chances that cells will mutate during the division process and become cancerous.
Squamous Cell Carcinoma
This form of skin cancer is often caused by exposure to the sun. Firm and often raised tumors usually occur in the abdomen or genitals, but can also occur on the feet, which can be painful and cause limping. Scientists believe there may also be a connection between the papilloma virus and the development of squamous cell tumors in certain dogs. The feline immunodeficiency virusFeline immunodeficiency virus
Feline immunodeficiency virus is a lentivirus that affects domesticated housecats worldwide and is the causative agent of feline AIDS. From 2.5% up to 4.4% of cats worldwide are infected with FIV...
(FIV) has also been linked to the development of squamous cell carcinoma
Squamous cell carcinoma
Squamous cell carcinoma , occasionally rendered as "squamous-cell carcinoma", is a histologically distinct form of cancer. It arises from the uncontrolled multiplication of malignant cells deriving from epithelium, or showing particular cytological or tissue architectural characteristics of...
in cats, although it is unclear what role the virus plays in the development of these tumors.
Mast Cell Tumors
These skin cancers, which occur in the mast cells of the immune systemImmune 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...
, are the most common skin tumors in canines. 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 are the second most common skin tumor in the cat, accounting approximately for 20% of all skin tumors. Veterinarians don’t know what causes mast cell tumors to develop, although there have been cases where they have been linked to inflammation or irritants on the skin. Evidence suggests genetic
Genetic
Genetic may refer to:*Genetics, in biology, the science of genes, heredity, and the variation of organisms**Genetic, used as an adjective, refers to heredity of traits**Gene, a unit of heredity in the genome of an organism...
factors are often important, and the hormones estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
and progesterone
Progesterone
Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
may also affect cancer growth.
Basal Cell Tumors
This is the most common type of skin cancer in cats. It is more common in older cats, often appearing as a single growth on the head. Basal cell tumors occur as small nodular growths beneath the skin, often next to each other, producing solid sheets of bumps. They also tend to occur on the back and upper chest. Basal cell tumors enlarge locally and spread by direct extension. They do not usually metastasize.Basal cell tumors are most commonly seen in Siamese
Siamese
Siamese most commonly refer to:*The Thai language*The Thai people*Someone or something from Thailand: see Siam *Siamese *Siamese twinsAmongst animals:*Siamese Crocodile*Siamese mud carp...
and domestic longhaired cats. Rarely, basal cell tumors become malignant
Malignant
Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...
. This occurs primarily in Persian cats.
Signs and symptoms
Skin tumors are usually discovered by pet owners as abnormal growths on the skin while examining or grooming their pets. Most benignBenign
A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...
tumors are slow growing and painless, with well defined boundaries and freely movable. In contrast, malignant tumors tend to be rapidly growing and often ulcerated with ill-defined boundaries.
Cats and dogs sometimes experience itchiness because of the cancer, which might cause them to scratch or chew at the affected area. This will often lead to redness of the skin or a flaky appearance.
Diagnosis
Typically, either cytologic or histopathologic analysis of the suspected mass is done prior to initiating treatment. The commonly used diagnostic procedures for skin tumors are fine-needle aspiration cytologyCytopathology
Cytopathology is a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by Rudolf Virchow in 1858. A common application of cytopathology is the Pap smear, used as a screening tool, to detect precancerous cervical lesions and prevent cervical...
and tissue 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...
.
Cytology is an important tool that can help the veterinarian distinguish a tumor from inflammatory lesions. The 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...
technique used will largely depend on the tumor's size and location. Small masses are usually completely excised and sent to the pathology
Pathology
Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
lab to confirm that the surrounding healthy tissues that were excised along with the tumor do not contain any cancer cells. If the tumor is larger, a small sample is removed for analysis and depending on the results, appropriate treatment is chosen. Depending on the tumor type and its level of aggressiveness, additional diagnostic tests can include blood tests to assess the pet’s overall health, chest X-rays to check for lung metastasis, and abdominal 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...
to check for 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...
to other internal organs.
Treatment
The specific treatment will depend on the tumor's type, location, size, and whether the cancer has spread to other organs. Surgical removal of the tumor remains the standard treatment of choice, but additional forms of therapy such as radiation therapyRadiation 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...
, chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
, or immunotherapy
Immunotherapy
Immunotherapy is a medical term defined as the "treatment of disease by inducing, enhancing, or suppressing an immune response". Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies. While immunotherapies that reduce or suppress are...
exist.
When detected early, skin cancer in cats and dogs can often be treated successfully. In many cases, a 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...
can remove the whole tumor, as long as the healthy tissues removed from just outside the tumor area do not contain any cancer cells.