Skin cancer in dogs is the proliferation of abnormal skin cells that manifest as dense lumps or bumps on the skin. 

There are many types of skin cancer in dogs, such as mast cell tumors, melanomas, squamous cell carcinomas, basal cell tumors, papillomas, histiocytomas, and sebaceous gland tumors. 

Symptoms of skin cancer in dogs include a visible lump of tissue somewhere in the body. The skin cancer lump on dog looks like a firm bump that grows bigger over time. 

An early stage dog skin cancer black spot is seen in skin cancers like melanomas, which affect the melanocytes. The tumors are either benign or malignant. 

Benign tumors are harmless masses that do not spread or cause harm to other parts of the body. Malignant tumors are dangerous and able to metastasize.  

A dog skin cancer black spot is treated through surgical removal of the tumor, along with radiation therapy, chemotherapy, or immunotherapy, depending on the type and stage of the cancer.

What is Skin Cancer in Dogs?

Skin cancer in dogs is a type of cancer wherein a proliferation of abnormal skin cells creates masses in the body. Skin cancer on dogs is one of the more commonly diagnosed cancers in canines, as dog skin is constantly exposed to carcinogenic substances and the environment. 

Skin cancer occurs due to external factors such as solar radiation, viruses, and harmful chemicals. Hormonal changes, genetics, and breed are linked to skin cancer in dogs in some cases. 

The tumors vary in shape, color, size, and localization on the dog’s body. A cancerous black growth on dog requires prompt identification and treatment because a skin cancer lump in dog has the potential to metastasize into other tissues and organs. 

What Causes Skin Cancer in Dogs?

The causes of skin cancer in dogs are listed below.

• Genetics: The exact mechanism of the hereditary nature of skin cancer in dogs is not well established, but genetics are considered a significant factor in most literature. Skin cancer in humans is associated with familial inheritance. There are hundreds of skin cancer types that occur in humans, and “many are known to have familial and/or inherited components, either in isolation or as part of a syndrome with other features,” according to the National Cancer Institute at the National Institutes of Health (NIH). 
• Chemicals: Chemical carcinogens are substances that cause cancer by affecting cellular components. Common carcinogens include nickel, uranium, benzidine, benzene, radon, vinyl chloride, cadmium, and asbestos. Increased exposure to these chemicals can induce skin cancer in dogs. 
• Radiation: Solar exposure and increased UV radiation are common environmental factors that influence the status of skin cells. UV radiation damages the skin's cellular DNA, affecting cellular growth and replication. Affected skin cells grow out of control and cause the growth of skin tumors. 
• Breed: Squamous cell carcinomas appear in Standard Schnauzers, Basset Hounds, and Keeshonds. Scottish Terriers and Schnauzers have high occurrences of malignant melanomas. Melanocytomas occur in Miniature Schnauzers, Doberman Pinschers, and Airedale Terriers. 
• Viruses: The canine papillomavirus (CPV1) is dogs' most common viral cause of papillomas. Papillomas are small, benign tumors of the mouth found on the lips, gums, and mouth. The canine papillomavirus affects young dogs and is transmissible through contact with other affected animals. 

What are the Symptoms of Skin Cancer in Dogs?

The symptoms of skin cancer in dogs are listed below.

• Lumps on the Skin: The sudden appearance of lumps or bumps on the skin is the most common sign of skin cancer in dogs. The lumps are palpable and occur on any part of the body. Lumps grow in size when left untreated and cause discomfort and uneasiness. 
• Poor Appetite: Skin cancers have the ability to metastasize and spread. The tumors invade other tissues and organs, increasing the severity of the problem. Lack of appetite is a typical response to pain and discomfort and is an initial sign that the dog feels unwell.
• Signs of Pain: Tumors attach firmly to underlying tissue and vessels. The attachments cause associated pain evidenced by vocalization, lack of energy, changes in gait, and lack of responsiveness. Certain tumors grow and develop into sores and ulcers. 
• Sores: Mast cell tumors are common skin cancers in dogs that develop into sores. The tumors appear as red and inflamed masses of tissue that grow into ulcerations. The ulcerations turn into infected, suppurative, and bloody sores. 
• Skin Discoloration: Melanomas are cancers that affect the body's melanocytes or pigment cells. Early stages of the disease consist of raised and discolored patches of skin that eventually progress into larger tumors. Benign melanomas are more commonly diagnosed than malignant forms. 

How is Skin Cancer Diagnosed in Dogs?

Skin cancer in dogs is diagnosed using laboratory tests. A veterinarian conducts a thorough history-taking and physical exam to assess the presence and type of cancer. 

The initial test is performed using a needle biopsy or fine needle aspirate. A needle is inserted into the mass, and the compressed tissue inside is collected and placed on a glass slide for examination. 

Punch or tissue biopsy is similar but requires a larger part of the suspicious mass. A section of the mass is removed and sent to a veterinary pathologist for identification of the type of cancer in dogs.

Radiograph assess for possible metastases in other parts of the body, while a CT (Computed Tomography) scan offers advanced imaging to determine the extent of malignancy in metastatic skin cancers in dogs. 

Does Dog Skin Cancer Cause Itchiness?

Yes, dog skin cancer causes itchiness. Itchy skin is a side effect of the inflammatory response. The cellular mechanism of inflammation involves recruiting pro-inflammatory cells, cytokines, and histamine, all itch-inducing chemical signals. 

Mast cell tumors release large amounts of histamine during mass degranulation. The mass degranulation causes signs that are similar to allergies, including swelling and itchy skin in dogs. 

What are the Different Types of Skin Tumors in Dogs?

The different types of skin tumors in dogs are listed below:

• Mast cell tumors: Mast cell tumors (MCT) are skin cancers of mast cell origin. MCTs are the most common types of skin cancer tumors. Mast cells are involved in allergic response and release large amounts of histamine. The histamine release triggers allergy-like symptoms in dogs. The tumors occur anywhere in the body, including the limbs, lower abdomen, chest, and prepuce. MCTs are benign or malignant and vary in size. Breeds commonly affected by MCT are Pugs, Rhodesian Ridgebacks, Boxers, and Boston Terriers. 
• Melanomas: Melanomas are skin cancers of melanocyte origin. Melanocytes are the pigment cells of the body that color the skin. The tumors most commonly develop on sparsely-haired areas such as the head and forelimbs. Breeds such as Miniature and Standard Schnauzers, Doberman Pinschers, golden retrievers, Irish Setters, and Vizslasa are commonly affected with melanomas. 
• Limpomas: Lipomas are skin cancers of lipocyte origin. Lipocytes are known as the “fat cells” of the body. Lipomas occur in older, obese females of breeds such as Doberman Pinschers, Labrador Retrievers, Miniature Schnauzers, and mixed-breed dogs. Limpomas are benign, but liposarcomas are a malignant counterpart. 
• Squamous Cell Carcinoma: Squamous cell carcinomas are malignant tumors of squamous cell origin. They are one of the most frequently diagnosed diseases in older dogs. The tumors develop on the lower abdomen on sparsely-haired skin. Breeds such as Bloodhounds, Basset Hounds, and Standard Poodles are most commonly affected by the disease. 
• Papilloma: Papillomas or warts are skin growths caused by papillomaviruses. The virus is spread through contact with an infected animal or contaminated fomites. Papillomas have an appearance similar to cauliflower. The warts appear on the mucous membranes, such as in or around the lips and mouth. 

What Treatment Options Are Available for Dogs with Skin Cancer?

The treatment options available for dogs with skin cancer are listed below:

• Surgery: The best way to remove tumors in dogs is through surgical excision. Benign tumors are resolved through resection of the growths. Surgery is curative in non-complicated skin cancers. Metastatic tumors are removed with surgery, but invasive tumors are at high risk for excision and are treated by other methods. 
• Chemotherapy: Intravenous medication specifically targets rapidly dividing cells, such as cancer cells. Chemotherapy is performed with surgical removal to remove residual cancer cells. There is a significant risk of harming the dog’s organs, such as the stomach, mouth, and reproductive organs, since chemotherapy targets rapidly dividing cells.
• Immunotherapy: Immunotherapy vaccines are available for certain types of dog skin cancer. The vaccine contains a killed version of the cancerous cells. The cells circulate through the dog’s system, stimulating antibody production to attack and destroy the cancerous cells. The therapy is combined with other treatments.  
• Radiation Therapy: Radiation therapy uses a focused radiation beam to target cancer cells. The goal is to destroy the tumors' cellular makeup, which causes the cancer cells to die. Radiation therapy is not used as a solo treatment but is combined with other forms of treatment, such as surgery and chemotherapy.
• Palliative Care: Dogs with late-stage metastatic skin cancer are too sick to be treated thoroughly. Palliative care makes the dog as comfortable as possible while undergoing skin cancer. The dog is put on long-term pain management therapy to ease living with the disease. 

What are the Early Signs of Skin Cancer in Dogs?

The early signs of skin cancer in dogs are lumps on the skin, odd discoloration, and behavioral changes. Dogs with skin cancer do not immediately show signs of distress. 

Early signs of skin cancer are when the skin starts showing lumps or bumps that were not previously there. Any bump on a dog’s skin is a cause for concern and is best examined immediately by a veterinarian. 

Dogs start to feel discomfort the longer the disease persists, observed as a lack of appetite, lack of energy, and decreased playfulness. 

Can Dogs Develop Melanoma Skin Cancer?

Yes, dogs can develop melanoma skin cancer. Melanomas are skin cancers that originate from melanocytes or pigment cells. Melanomas are observed in dogs with darkly-pigmented skin. 

Most melanomas are benign, but metastatic melanomas occur. Metastatic melanomas are more severe as they spread to other organs. Malignant melanomas more commonly manifest in senior dogs.

Can Skin Infections in Dogs Progress into Cancer?

No, skin infections in dogs cannot progress into cancer. Skin cancer is complicated by secondary skin infections and not vice versa. Sores that occur as a side effect of skin cancer are easily mistaken for superficial skin infections. 

Persistent non-healing sores are indicative of cancer. Dog skin infections that do not resolve with antibiotic therapy are candidates for fine needle aspiration or biopsy.  

Are Certain Dog Breeds More Prone to Skin Cancer?

Yes, certain dog breeds are more prone to skin cancer. Each type of skin cancer in dogs has associated breed predispositions. 

Squamous cell carcinomas occur in Standard Schnauzers, Basset Hounds, and Keeshonds. Scottish Terriers and Schnauzers are highly prone to malignant melanomas. 

Melanocytomas occur in Miniature Schnauzers, Doberman Pinschers, and Airedale Terriers. 

Mast cell tumors are common in Boxers, Pugs, Rhodesian Ridgebacks, and Boston Terriers.

How can Dog Owners Prevent Skin Cancer in Their Pets?

Dog owners can prevent skin cancer in their pets by taking good care of the dog’s skin. Establish a habit of routinely inspecting the dog’s body, preferably during bathing or grooming sessions. 

Avoid excessive UV exposure in dogs during times of the day when the sun is strongest. Abnormalities in the skin or growths that were not previously present are early signs of skin cancer. Take the dog to the veterinarian if symptoms are observable. 

How long can a Dog Live with Skin Cancer?

A dog can live several months to several years with skin cancer, with 15-18 months on average for Stage 1 tumors. The lifespan of a dog with skin cancer varies depending on the type of cancer. Benign cancers are easily cured with surgical excision of all the tumors. Metastatic tumors require longer courses of treatment and exhaustive therapies. Dogs that are diagnosed too late with skin cancer have a poor prognosis of up to 10 months survival. 

What does Skin Cancer Look Like on Dogs?

Skin cancer on dogs looks like raised tissue patches on a dog’s skin. The bumps are firm or soft to the touch. The tumors vary in size, shape, and color depending on the type of cancer. Some tumors are smooth, while others are chunky or textured. Skin cancer is not always evident during early stages and resembles a mole. 

Is Skin Cancer in Dogs Treatable?

Yes, skin cancer in dogs is treatable. Benign dog skin cancer is treated with complete excision of all tumors. Malignant tumors are managed with additional therapeutic options such as chemotherapy, radiation, or immunotherapy. 

The chances of complete resolution of malignant skin tumors depend on the stage and severity of the damage. Dogs diagnosed too late are very sick and have a poor prognosis. 

Are Skin Tumors in Dogs Always Cancerous?

No, skin tumors in dogs are not always cancerous. Cancerous tumors are growth with the potential for malignancy, which is not always the case. A larger percentage of skin tumors in dogs are benign. Examples of benign skin tumors in dogs are cysts, papillomas, adenomas, lipomas, and histiocytomas.

Can Skin Tumor in Dogs be Removed?

Yes, skin tumors in dogs can be removed. Benign skin tumors are best removed by surgical excision. Malignant skin tumors are removable if an excision does more good than harm. Metastases on vital organs are usually left alone and treated with other therapeutic methods such as chemotherapy, radiation therapy, and immunotherapy.