What Is A Lump On A Dog That Grows And Shrinks?

What is a Lump on a Dog?

A lump on a dog refers to any abnormal bump, mass, or swelling on your dog’s body. Lumps can appear anywhere on a dog, including the legs, belly, head, neck, armpits, and groin area. Lumps may be skin growths, fatty tumors, abscesses, cysts, hematomas, or cancerous tumors.

Some of the most common locations for lumps on dogs include the legs, belly, head, neck, and behind the front legs. Lumps can range greatly in size – from very small, pea-sized lumps to large masses over 10 cm wide. They may be soft or firm, movable or attached to underlying tissues.

Lumps on dogs are categorized as either benign (non-cancerous) or malignant (cancerous). Common benign lumps include lipomas (fatty tumors), sebaceous cysts, abscesses, and hematomas. These lumps tend to grow slowly, have clear borders, and don’t invade other tissues. Malignant lumps like mast cell tumors and melanoma tend to have irregular borders, grow rapidly, and can spread to other parts of the body. It’s important to get all new, growing, or changing lumps checked by a vet.



Possible Causes of Lumps on Dogs

There are several possible causes for lumps on dogs. Some of the most common causes include:

Fatty tumors (lipomas) – Fatty tumors are benign lumps consisting of fat cells. They are soft, movable lumps that are usually painless. Fatty tumors are very common in older dogs. While generally harmless, in rare cases they can interfere with movement if they grow very large.

Warts – Warts are small, rough lumps on the skin caused by papillomavirus infection. They are benign but very contagious between dogs. Warts usually go away on their own but may need to be treated if they persist.

Allergic reactions – Allergic reactions to food, medications or insect bites can cause hives, which are red, raised lumps on the skin. They are usually intermittent and may come and go.

Abscesses – Abscesses are pockets of pus caused by bacterial infections. They form firm, painful lumps under the skin. Abscesses need antibiotic treatment and often need to be drained.

Hematomas – Hematomas occur when blood vessels rupture and blood pools under the skin. This causes a soft, fluid-filled lump. Hematomas usually resolve on their own but may need draining for faster healing.

Cysts – Cysts are fluid-filled sacs under the skin. They form firm, dome-shaped lumps. Cysts can become infected and may need draining or surgical removal.

If your dog develops any new lumps or bumps, it’s a good idea to have your vet examine them to determine the cause and recommend any needed treatment.

Lumps That Grow and Shrink

Some types of lumps on dogs may increase and decrease in size over time. These are referred to as fluctuating or cycling lumps. There are a few potential causes for lumps that seem to grow and shrink repeatedly:

Hematomas are a common cause of fluctuating lumps on dogs. A hematoma forms when blood vessels leak blood under the skin, causing a fluid-filled swelling. As the body reabsorbs the blood, the hematoma will shrink and then refill again in a cyclical pattern. Hematomas often occur after trauma or injury, but can also develop spontaneously in older dogs (https://www.texvetpets.org/article/lumps-bumps-when-is-it-serious/).

Cysts can also fluctuate in size over time. Sebaceous cysts filled with fatty secretions may enlarge and rupture, draining the contents, before refilling again. This can make them appear to grow and shrink repeatedly (https://www.petmd.com/dog/symptoms/lumps-bumps-and-cysts-dogs).

Diagnosing Fluctuating Lumps

If your dog has a lump that seems to grow and shrink, it’s important to take them to the vet for a proper diagnosis. The vet will start by performing a thorough physical exam of the lump, noting its location, texture, mobility, and how it responds to touch. They may try to identify where the lump is originating from – whether it’s arising from the skin, underlying muscle or bone, etc.

To identify the cause of the fluctuating lump, the vet may recommend a fine needle aspirate (FNA). This involves inserting a small needle into the lump and drawing out some cells for examination under a microscope. FNA allows the vet to see if the cells are normal, inflammatory, or cancerous. This can help rule out or diagnose lumps like fatty tumors, abscesses, cysts, and mast cell tumors.

If the FNA is inconclusive, the vet may recommend a biopsy to examine the cells in greater detail. This involves surgically removing a small piece of the lump for pathology testing. Biopsies are more invasive than FNAs but can provide a definitive diagnosis.

Proper diagnosis of a fluctuating lump requires expertise, so it’s important to have your vet perform an exam and recommend the appropriate diagnostic tests. This will allow treatment to begin as early as possible if the lump does turn out to be cancerous. Waiting and watching is not advised, as some cancers like mast cell tumors can spread quickly. Consult your vet if you notice any new, changing lumps on your dog (1).

Treating Fluctuating Lumps

The treatment for fluctuating lumps on dogs depends on the underlying cause. Some common treatment options include:

Draining hematomas and cysts – For fluid-filled lumps like hematomas or sebaceous cysts, the vet may recommend draining the fluid to relieve pressure and shrink the lump. This may need to be repeated periodically as the lump refills with fluid over time.

Surgery for benign masses – For benign fatty tumors, histiocytomas, and other benign masses, surgical removal is often curative. The vet will remove the entire mass with clean margins to prevent recurrence.

According to vetmed.illinois.edu, surgery may be recommended for malignant tumors as well, along with chemotherapy or radiation therapy.

The specific treatment will depend on the type of lump, its location, if it’s cancerous, and other factors. Regular veterinary exams and cytology/biopsies are important for accurate diagnosis and determining the ideal treatment plan.

When to See the Vet

If your dog develops any new, growing, or fluctuating lump, it’s important to have your vet examine it as soon as possible. Lumps that change in size quickly could potentially indicate something more serious that requires prompt veterinary attention.

According to Dixie Animal Hospital, you should have your vet evaluate any new lumps within 1-2 days of noticing them. They recommend not waiting longer than 2-4 weeks, even for lumps that seem small and harmless.

Additionally, the veterinarians at AZVet advise seeking prompt veterinary care for any lump that impacts your dog’s mobility or function. A lump that interferes with their movement, walking, eating, bowel movements, etc. warrants urgent vet examination to diagnose the cause.

While some lumps may be benign, it’s crucial to rule out cancer or other issues. Catching concerning lumps early maximizes treatment options and outcomes. Don’t hesitate to contact your veterinarian if you have any questions or concerns about a new or changing lump on your dog.

Caring for a Dog with Lumps

Caring for a dog with lumps requires monitoring the lump closely and following any treatment instructions from your veterinarian (1). Here are some tips for caring for a dog with lumps:

Monitor the Lump
Keep an eye on any lumps or bumps on your dog. Note the size, shape, color, texture, and if it seems to cause pain or irritation. Track any changes and report them to your vet. Monitoring helps determine if treatment is working or if the lump is getting worse.

Avoid Irritating the Area

Try to prevent your dog from licking, scratching, biting or rubbing a lump. This can cause trauma, inflammation and potential infection (2). You may need an Elizabethan collar to restrict access to the area. Gently wash irritated lumps with a mild soap and pat dry.

Follow Treatment Instructions
If your vet prescribes medication, carefully follow dosing instructions. Give all medication as directed for the full course of treatment. Keep track of any side effects. Limit activity if advised during recovery periods. Follow any wound care or dressing change instructions.

Caring for a dog with lumps takes patience and attention. Monitor changes, prevent irritation, and follow your vet’s advice. Proper at-home care can help treat lump conditions and support your dog’s comfort during recovery.

(1) https://www.rspcapetinsurance.org.au/pet-care/dog-care/canine-guide-lumps-bumps-on-dogs

(2) https://www.4pawsanimal.com/services/cats-dogs/blog/step-step-guide-lumps-and-bumps

Preventing Lumps in Dogs

There are several ways to help prevent lump formations in dogs:

Get routine veterinary exams to identify any lumps when they first develop. Catching them early allows for better treatment options.

Maintain your dog at a healthy weight. Obesity is a risk factor for fatty tumors like lipomas. Feeding a nutritious diet and ensuring adequate exercise can help prevent excess weight gain.

Limit sun exposure, especially during peak hours. Sun overexposure raises the risk of solar-induced lumps like skin cancer. Apply dog-safe sunscreen and provide shade when outside.

Give omega-3 supplements like fish oil. Omega-3s have anti-inflammatory properties that may inhibit lump growths like lipomas. Consult your vet on an appropriate supplement and dosage for your dog.

Choose a high quality diet with antioxidants. Antioxidants fight cell damage linked to lump formations. Discuss the best food options with your veterinarian.

Monitor for any changes and inform your vet of any lumps found. Early evaluation and treatment is key to better prognosis.

While not all lumps can be prevented, the above steps can reduce the risks in dogs. Catching any lumps promptly and managing them appropriately is key.

Outlook for Dogs with Lumps

The outlook for dogs with lumps depends on the cause and how quickly treatment is sought. Many lumps on dogs are benign fatty tumors called lipomas that do not require treatment 1. Even malignant lumps like mast cell tumors often have a good prognosis if treated early before spreading to other areas of the body 2.

Seeking prompt veterinary care is crucial for the best prognosis. Vets can assess the lump, perform diagnostic tests like fine needle aspiration or biopsy, and determine the appropriate treatment plan. Catching lumps when they first appear gives the best chance for successful removal. Monitoring lumps at home and not waiting for them to resolve on their own is advised.

With appropriate treatment guided by a veterinarian, the majority of dogs go on to live normal lives after lump removal. Benign fatty tumors may regrow but are not life threatening. Cancerous lumps can be fully cured if caught early before spreading. Regular vet checks and prompt care when lumps appear offer dogs the best prognosis.

When to Seek a Specialist

In some cases, you may need to seek out a specialist veterinarian for your dog’s fluctuating lump. This is especially important if the lump could potentially be cancerous or is located in a delicate area of the body.

According to Dixie Animal Hospital, you should have a specialist examine any lump that seems abnormal – things like irregular shape, rapid growth, or firm/hard feeling. A specialist like an oncologist may order additional diagnostic tests like biopsies to check for cancer.

Lumps in sensitive areas like the face, groin, armpits or chest should also be evaluated by a specialist, according to AZVet. Surgery in these areas carries greater risk, so you need an experienced surgeon. A specialist can also provide targeted treatment if the lump turns out to be malignant.

Getting an early cancer diagnosis and proper treatment plan from a specialist can greatly improve outcomes for your dog. Don’t delay on getting professional help if your dog’s lump seems highly unusual or worrisome.

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