Lipomas in Dogs
Can (or should) anything be done about lipomas (also known as fatty tumors)?
Article by CJ Puotinen and Mary Straus, published in the Whole Dog Journal, October 2012
Photo of dog above with lipomas behind his left elbow and on his left side.
Uh-oh. What’s this lump? Any growth on your dog’s body deserves attention, especially one that wasn’t there last time you checked. It could be a sebaceous cyst (a sac filled with sebum, a cheesy or oily material, caused by clogged oil glands in the skin), an abscess (a pus-filled swelling caused by infection), or – everyone’s worst nightmare – a cancerous tumor. But in most cases, the lumps we discover as we pet and groom our dogs are lipomas, which are benign (non-cancerous) fat deposits, also known as fatty tumors.
An estimated 1.7 million dogs are treated in the United States for lipomas every year, and according to one survey, American veterinarians average 25 lipoma removals annually at a cost to owners of $635 million.
Lipomas tend to emerge as dogs reach middle age and increase in number as they get older. A dog with one lipoma is likely to get more. They are most often found on the chest, abdomen, legs, or armpits (axillae). These fatty lumps aren’t painful and they usually stay in one place without invading surrounding tissue. Dogs aren’t the only animals with lipomas, as they are common in humans and parakeets, and they occasionally develop in cats and horses.
While canine lipomas are frequently associated with overweight females, their greatest risk factor may be genetic. “I’ve heard all kinds of theories,” says Tia Nelson, DVM, of Helena, Montana. “Some veterinarians are convinced that lipomas are the result of over-vaccination, commercial pet food, grain-based diets, and exposure to environmental toxins. Although most dogs with lipomas fit that description, I can show you plenty of lumpy dogs who were holistically raised on grain-free raw food and minimal vaccinations, including some of my own. The simple fact is that some dogs are going to develop lipomas no matter what you do.”
Any dog can be affected, but lipomas seem most common in Labrador Retrievers, Doberman Pinschers, Miniature Schnauzers, Cocker Spaniels, Dachshunds, Poodles, Terriers, and mixed breeds.
Most lipomas are subcutaneous (occurring just beneath the skin's surface) and are moveable, not attached to skin or underlying muscle or tissue. They are usually small and either round or oval, the size of a marble or marshmallow, and soft or rubbery to the touch. A few feel more solid due to fibrous tissue or inflammation. Some grow to golf-ball size, and very large lipomas can resemble baseballs. A few grow long and wide.
Because there’s no way to tell whether a lump is a lipoma just by feeling it, veterinarians remove and inspect fluid from inside the lump in a biopsy procedure called fine-needle aspiration to confirm that the growth contains only fatty cells. Some are concerned about the potential for fine-needle aspirate to spread cancer if the lump is not benign, and this concern is reasonable for tumors in the abdomen or heart (especially if they are filled with fluid, which can be determined with ultrasound) or in the urinary tract, including bladder and prostate. When aspirating subcutaneous solid tumors that might be confused with lipomas, however, the risk is small and outweighed by the advantages of having an accurate diagnosis.
The usual recommendation for fatty tumors is to wait and watch. Sometimes lipomas develop rapidly but in most cases their growth is slow. They rarely cause problems unless they become exceptionally large or their location creates mechanical problems. For example, a lipoma in the armpit can affect a dog’s gait, while one in the sternum (chest area) can cause discomfort whenever the dog lies down, and a lipoma in the neck area, if it grows large enough, can interfere with breathing and proper collar fit.
“I never do surgery on benign lipomas unless they are physically impeding ambulation or other function,” says Stacey Hershman, DVM, of Hastings-on-Hudson, New York. “I never remove a lipoma for cosmetic reasons since I have seen dogs get ill or go into liver failure after lipoma surgery even though their pre-op bloods were normal. Therefore I recommend to my clients that we leave them alone unless there is a medical reason to remove them. A few years ago a dog came in with such a huge lipoma under his armpit that he could not walk, and I removed it for functional reasons.”
Some lipomas grow so rapidly that they might be something else, such as a liposarcoma. This rare, malignant fatty tumor usually does not metastasize (spread to other parts of the body) although it can be aggressive and fast-growing. Other tumors that occur on or under the skin that could be mistaken for lipomas include sebaceous adenomas, mast cell tumors, hemangiosarcomas, and hemangiopericytomas. If there is any question about diagnosis, removal may be the safest option.
Occasionally lipomas invade connective tissue between muscles, tendons, bones, nerves, or joint capsules. Called infiltrative lipomas, these usually occur in the legs but can affect the chest, head, abdominal body wall, or perianal region. Infiltrative lipomas can cause pain, muscle atrophy, and lameness by interfering with movement. Unlike normal lipomas, infiltrative lipomas can be difficult to remove completely and often regrow. Infiltrative lipomas are most common in Labrador Retrievers and Doberman Pinschers.
Not all infiltrative lipomas cause problems. Suzi Faulkner is president of the Atlantic Rottweiler Rescue Foundation (ARRF), which rescued Gus, a 3-year-old Rottweiler, in January 2011. “Gus was pulled from a shelter in Tennessee,” she says. “When our volunteers picked him up, they discovered a cluster of lumps around his shoulder blade. A veterinarian removed the small lumps, but the large lump had infiltrated Gus’s shoulder and removing it would mean removing part of the shoulder. It tested benign, so it was left alone.”
Faulkner feared that his lipoma would prevent Gus from finding a home, but Scott Adelman of Owings Mills, Maryland, fell in love with Gus and adopted him as soon as he recovered from surgery. A year and a half later, Adelman reports that Gus is able to run and play normally, and he is not in pain. “Gus is the best dog in the world,” he says.
Some lipomas can be removed with just a sedative and local anesthetic. Surgery for large, inconveniently placed, or multiple lipomas requires general anesthesia. Ordinary lipomas rarely grow back after removal, but others may occur. Surgery for infiltrative lipomas is more complicated and these growths often recur within 3 to 16 months. Radiation therapy may prevent or delay their recurrence, while chemotherapy provides no benefit.
Small lipomas used to be injected with a 10-percent solution of calcium chloride, which caused the tumors to become smaller, but this treatment is no longer recommended because of the irritation and severe skin damage it causes.
Liposuction, the same procedure that vacuums fat out of humans in cosmetic surgery, is in many cases less invasive, less painful, and faster healing than surgical removal.
In 2006, a 12-year-old Kelpie-cross named Patch made headlines in Sydney, Australia, for being the first Australian dog to undergo liposuction. Patch had several lipomas, one of which, on his hind leg, threatened to cripple him within months. Remembering a European veterinarian who performed liposuction on a dog using the suction tool normally used to clean up fluids during surgery, an Australian vet suggested trying this approach on Patch. The hour-long procedure removed six fatty tumors weighing two kilograms (4.4 pounds, or 10 percent of Patch’s body weight). He was soon happy and playful again.
In January 2007, the Journal of Small Animal Practice reported the liposuction removal of three giant lipomas from a dog in Leipzig, Germany. The extremely obese patient suffered from arthritis and hind-leg lameness, plus irritation caused by an armpit lipoma. Previous treatment involving dietary weight loss and non-steroidal anti-inflammatory drugs had failed. Liposuction of the three lipomas resulted in a three-kilogram weight loss (6.6 pounds, or 10 percent of the dog’s body weight).
In a retrospective study published in July 2011, the Journal of Small Animal Practice reviewed the use of liposection on multiple lipomas from 20 dogs. The treatment successfully removed 73 of 76 lipomas (96 percent). Simple, encapsulated lipomas measuring less than 6 inches in diameter were the easiest to remove and resulted in minimal risk of complication. Giant lipomas contained fibrous material that interfered with the removal of fat and had a high risk of bruising, hematoma, and seroma (fluid-filled swelling), especially in the groin area. Regrowth occurred nine months to three years later in 28 percent of the lipomas. Liposuction is not recommended for infiltrative lipomas.
The newest lipoma treatment for dogs and humans is the injection of collagenase, an enzyme that breaks the peptide bonds in collagen, the fibrous protein that connects body tissues. Developed by BioSpecifics Technologies Corporation and marketed as XIAFLEX® in the U.S. and XIAPEX® in Europe and Eurasia, collagenase is being tested in clinical trials.
One preliminary trial tested three healthy dogs with multiple subcutaneous lipomas that were benign, superficial, and easily measurable. One lipoma on each dog was injected with collagenase and another was left untreated for use as a control. Ninety days after injection, a CT scan showed that the treated lipomas on two of the dogs had disappeared completely and the third dog’s treated lipoma was only 7 percent of its original size. By contrast, the control lipomas had grown. Altogether, the treated lipomas showed a 97-percent reduction in size while the untreated controls increased by 23 percent.
BioSpecifics has initiated a placebo-controlled, single-injection randomized Phase II clinical trial to evaluate the efficacy of XIAFLEX for treatment of benign subcutaneous lipomas in 32 canines in a study to be completed in 2013. This will be followed by a Phase III clinical trial before the product becomes commercially available. See Resources below for details.
Because lipomas are so common in overweight dogs, one obvious treatment is weight loss. In some cases, diet and exercise have reduced the size of existing lipomas and may have helped prevent new ones from developing. Even if your dog’s lipomas don’t shrink as a result, helping an overweight dog trim down should help her feel better and be more active.
Switching to a raw, grain-free diet has been said to help some dogs, although most raw diets are high in fat, which may be counterproductive.
Limiting vaccinations may help some dogs, especially if lipomas tend to occur after vaccination.
“In my practice I have been following several dogs who are now 6 to 14 years old,” says Judith K. Herman, DVM, of Augusta, Maine. “So far these dogs, all of whom received minimal vaccinations and are fed raw, have not developed any lipomas. Most are Jack Russell Terriers, Belgian Tervurens, Labrador Retrievers, and Golden Retrievers.”
While acupuncture involves the insertion of needles along the body’s meridians, acupressure applies finger touch or massage to the same points. As Amy Snow and Nancy Zidonis explained in “Truly Healing Touch” (WDJ, March 2009) and other WDJ articles, the basic principle underlying the healing process is that vital substances nourish the body while moving harmoniously through it. Two of these vital substances are chi (or qi), which is life-promoting energy, and blood, a nutrient-rich body fluid. In Traditional Chinese Medicine, "blood" includes other body fluids, such as synovial fluid in the joints or the nutrient-rich fluid within the spinal column.
“My dog Oak was a lipoma creator of great dimension,” says Snow, “and acupressure worked to resolve them for most of his life. In Traditional Chinese Medicine, a lipoma is a stagnation of body fluids. The challenge is to bring chi through the area to move or disperse the fluids. The longer they stay, the more difficult it is to resolve them because they become ‘cold.’ Additionally, the younger the dog, the more quickly lipomas can be resolved. As the dog ages, his system naturally slows down and this slowing leads to an increase in developing lipomas.”
Even as a two-year-old, Oak, who was an affectionate, easy-going Golden Retriever, created lipomas. “I’d run my hands over him almost every day to see if there were any new ones,” she says. “I had him checked for hypothyroidism to see if his metabolism was normal, and it was. Oak’s lustrous coat often hid the lipomas until they were obvious. But I did my best to locate them and get to work with acupressure massage, also called Tui Na in Chinese, as a way to increase the movement of chi and body fluids through each lipoma.”
For six years, Snow resolved Oak’s lipomas with these techniques. After age eight, although they remained small, his lipomas became a management issue and were not completely resolved. At age 11, one had to be removed because it hindered walking. The following year, Oak passed away with only a few minor lipomas.
“Lipomas are relatively superficial, just beneath the skin, and so are the meridians,” says Snow. “That’s why working along the meridians that pass through a lipoma works. If people use acupressure around a lipoma but not on meridian points, it will not be as effective and in fact may not be effective at all. Graduates of the Tallgrass Animal Acupressure Institute training program have shown the guardians/owners of dogs with lipomas how to perform some of these procedures on a consistent basis. Applying acupressure massage every day for six days, then taking a one-day break, then continuing for another five or six days and repeating the pattern until the lipoma is resolved seems to be an important element in ridding dogs of lipomas.”
For best results, consult a canine acupressure practitioner who can show you exactly which acupoints affect energy flowing through a specific lipoma, or practice on your own with the help of Acu-Dog: A Guide to Canine Acupressure.
Herbs have been used for millennia to treat every type of condition, and today’s science confirms the effectiveness of many ancient remedies. Turmeric (Curcuma longa), the root that gives Indian curries their distinctive color and flavor, has a long history of use in Ayurveda, the traditional medicine of East India, especially for digestive disorders and arthritis. Curcumin is the active ingredient responsible for turmeric’s anti-inflammatory and antioxidant properties.
Andrew Stowe of Fairfax, Virginia, gave turmeric root powder to Cayman, his 13-year-old yellow Lab/hound-mix, as part of a treatment for arthritis. Cayman had developed six large and medium-sized lipomas, and while he was taking turmeric, three of them disappeared and the others shrank. After six months the arthritis treatment stopped working (Cayman began limping again), so Stowe discontinued the treatment, at which point the dog’s lipomas returned and he developed even more. Stowe thinks the turmeric may have suppressed their growth.
The protocol Stowe followed for 80-pound Cayman combined turmeric powder with other supplements, beginning with a four-week dose of ¼ teaspoon turmeric powder morning and evening; then two weeks at ½ teaspoon twice per day; then ¾ teaspoon twice per day. It’s a good idea to begin any herbal treatment with small doses and increase gradually to the recommended amount, which in the case of turmeric is often ¼ teaspoon for small dogs, ½ teaspoon for medium-sized dogs and 1 teaspoon for large dogs daily. Give with food to prevent stomach upsets. Be sure your turmeric is Curcuma longa (verify the herb’s Latin name) and not an inexpensive substitute, and, because turmeric dyes everything yellow, wash your hands after handling.
Curcumin extract is much more concentrated than the powdered root. Recommended dosage varies, but one product made for dogs suggests giving 20 to 60 mg per 10 pounds of body weight daily. Higher doses, up to 2,000 mg twice a day for a large dog, are used to treat dogs with cancer. Combining curcumin with bromelain may increase absorption.
Herbalist Ingrid Naiman developed “Stone Free” Herbal Support for Kidney and Gallbladder using turmeric and other herbs. “It emulsifies fat,” she says. “We have seen it completely remove fatty deposits under the skin.”
Alyssia Greiner of Manassas, Virginia, tried a Chinese herbal treatment for her 9-year-old Border Collie, Zippity, when she developed a large lipoma on her right shoulder, another on her right ribcage, and a small one inside her left leg. Her veterinarian prescribed “Cluster Dissolving,” a traditional blend of 11 Chinese herbs.
“Zip has been on it for about six months,” says Greiner, “and there is a definite difference in size and softness. The one on her shoulder used to feel like a softball and people would freak out when they felt it, but several people familiar with her think it feels smaller, softer, and more pliable. The one on her leg felt like a large marble but is now softer and smaller. The rib cage lipoma feels very loose and fluid now. I don’t think they will dissolve completely, but as long as they are not getting bigger, I’m happy.”
Although homeopathy is often recommended as a support therapy for lipomas, many veterinary homeopaths report little or no success with homeopathy as a stand-alone treatment for fatty tumors.
Dr. Judith Herman in Augusta, Maine, is a veterinary homeopath, former president of the Academy of Veterinary Homeopathy, and chair of its certification committee. Classically trained homeopaths such as Dr. Herman use single remedies (not combinations) in response to their patients’ specific symptoms. “The correct remedy is the one that matches the patient's whole picture,” says Dr. Herman. “Lipomas are part of the chronic disease picture, not single entities.”
In 2004, Dr. Herman treated Anna, a 1-year-old Golden Retriever, for masticatory muscle myositis, an inflammatory muscle disease that produces jaw pain or an inability to open the jaw. At the time, Anna was eating grocery store kibble and taking prednisone. “Because she had diarrhea and her owners weren’t ready to forego allopathic treatment,” she says, “I suggested changing her food to a raw, home-prepared diet.”
Prednisone was discontinued after symptoms resolved, but when they returned, Dr. Herman treated Anna homeopathically. Within two months, her mouth functioned normally, but Anna later returned with a soft lump on her chest, which was diagnosed as a lipoma, and she again showed mild signs of myositis. She received the same homeopathic remedy as before but at a higher potency. One month later her mouth was back to normal and the lipoma had disappeared.
“Anna has had normal yearly visits since then without any sign of illness,” says Dr. Herman. “In 2010 she developed a yeast infection in her ears and I treated her with the same remedy as in 2004 because her symptom picture still matched the remedy. Her ears were fine within a month, and she is still doing well.”
Stephen Blake, DVM, of San Diego, California, reports, “I had a case at a no-kill shelter decades back where an 8-year-old Shepherd mix had a lipoma almost the size of a basketball on his back, hanging over his side. It was so big that the dog had problems running. I only treated him once with homeopathic Thuja 10M and within a month it dissolved. After two months all that was left was a large sack of skin hanging on the dog’s back.
"My reasoning for prescribing the Thuja was the fact that he had been vaccinated prior to the appearance of the lipoma. Homeopathic Thuja is a good choice in cases like this, where a lipoma appears after a vaccination.”
Aromatherapy’s essential oils (see “Essential Information,” WDJ January 2005) may help lipomas in some cases. Dr. Blake says, “As part of the healing protocol for all tumors, I use a combination of frankincense (Boswellia spp.), sandalwood (Santalum album), and Douglas fir (Pseudotsuga menziesii) to aid the body in its detoxification and healing process. I have the owner massage a small amount of these oils into the tumor daily until the body has no need for it.”
Jeannie Thomason, CVND (certified doctor of veterinary naturopathy), was working as a veterinary technician 24 years ago when one of her dogs developed a lipoma on her right shoulder. “I had seen many dogs have lipomas surgically removed only to come back again, usually bigger and more of them,” she says, “so there was no way I was going to go that route. I had been doing research on the healing properties of pure, therapeutic grade essential oils. I pulled out my frankincense and began to apply a couple of drops directly on the tumor and lightly rub it in. Within 48 hours I could see a remarkable difference in the size of the tumor – it was shrinking! I continued to apply the frankincense daily until the lipoma had totally disappeared.”
Canine aromatherapist Frances Fitzgerald Cleveland of Littleton, Colorado, uses full-strength grapefruit essential oil (Citrus x paradise), which is not a distilled essential oil but rather cold-pressed from the peel of fresh fruit. “This is a very cooling, cleansing, and decongesting oil, like lemon,” she says. “Grapefruit oil helps the body eliminate excess fluids and break down fats, plus it promotes a lightness of spirit. It is my first choice when working with lipomas. I find it aids in clearing the lymphatic system, helps with congestion of the skin, and is a tonic to the system. I have used it on two of my dogs with great success in keeping their existing lipomas from getting any larger and shrinking some to a smaller size."
Essential oils are usually diluted before being applied to dogs, but one or two drops of therapeutic-quality frankincense or grapefruit essential oil can safely be applied to an adult dog’s lipoma once or twice per day.
While lipomas can be unsightly, they are generally harmless and rarely cause problems. This is one situation where doing nothing is a completely acceptable option, once the diagnosis has been verified. Be thankful knowing that your dog has nothing worse than a lump of fat and not a cancerous tumor.
Some are reluctant to perform surgery on old dogs because of anesthesia risks or complications, but these risks are minimal in the case of most lipomas. Modern anesthesia protocols are far safer than they used to be, and complications are generally minor, usually limited to superficial infection or delayed healing. There is no reason not to remove lipomas from older dogs when they interfere with their quality of life.
Tia Nelson examined a 12-year-old Lab whose owners had made the painful decision to put her down because she just couldn’t get around any more. But her problem wasn’t old age, it was a five-pound lipoma on her side just behind and partly under her shoulder blade. “I removed it,” says Dr. Nelson, “and the dog enjoyed another two years.”
In a report published on his blog “Your Pet’s Best Friend,” Everett Mobley, DVM, of Kennett, Missouri, described Ling Ling, a 15-year-old Collie mix who developed a large tumor in front of her left shoulder. “It was about 6 inches long, 3 inches wide and 1.5 inches thick, which is pretty big, even for a 57-pound dog,” he says. “We did a fine-needle aspiration and it turned out to be a lipoma. Because Ling Ling was so elderly and the tumor was large enough to require lengthy surgery, plus it didn’t seem to be bothering her, we decided it was something she would probably die with, instead of something she would die from.”
But in May 2012, Ling Ling lost weight while her tumor grew. “It grew so much,” says Dr. Mobley, “that it appeared to have disrupted its own blood supply. There was a nasty-looking bulge that looked like it would soon die and rot and burst open. Not so good. She made it through 90 minutes of surgery like a champ. The tumor was so big it was like delivering a baby. It weighed three pounds and was as big as her head.”
Because the mass had disrupted the attachment of Ling Ling’s shoulder muscles, Dr. Mobley re-attached them. She made a full recovery.
For further reading:
“Liposuction for removal of lipomas in 20 dogs” by GB Hunt, et al. Journal of Small Animal Practice, Volume 52, Issue 8, pages 419-425, August 2011.
“Liposuction -- removal of giant lipomas for weight loss in a dog with severe hip osteoarthritis” by P. Böttcher P, et al. Journal of Small Animal Practice, Volume 48, Issue 1, pages 46-48, January 2007.
“Too old for tumor surgery?” by Everett Mobley, DVM. Your Pet’s Best Friend, July 26, 2012.
Acu-Dog: A Guide to Canine Acupressure by Nancy Zidonis, Amy Snow, et al. Tallgrass Publishers, 2011, paperback, 188 pages, $33.
Products and Practitioners:
“Stone Free” by Planetary Herbals, Ingrid Naiman, (800) 606-6226
“Cluster Dissolving” by Kan Herb Company, (800) 543-5233
“CurcuVet” by Thorne Research, (800) 228-1966
XIAFLEX (injectable collagenase), Biospecifics Technology, (516) 593-7000. Dogs with benign subcutaneous lipomas may be eligible to participate in a clinical trial conducted in Carlsbad, California by California Veterinary Specialists. For information contact Dr Sarit Dhupa, firstname.lastname@example.org, or Janette Velez, email@example.com, (760) 431-2273. See BioSpecifics Technologies Corp. Announces Initiation of Phase II Trial for Canine Lipomas for more information.
Frogworks, canine aromatherapy, Frances Fitzgerald Cleveland, Littleton, CO. (303) 973-8848 or (877) 973-8848
Tallgrass Animal Acupressure Institute, Larkspur, CO. Amy Snow, Nancy Zidonis, and practitioner referrals, (303) 681-3033
Atlantic Rottweiler Rescue Foundation (ARRF), Mooresville, North Carolina. (704) 929-2304
Stephen Blake, DVM, San Diego, CA. (858) 566-3588, thepetwhisperer.com
Judith K. Herman, DVM, Augusta, ME. (207) 623-1177, mainehomeopathicvet.com
Stacey Hershman, DVM, Hastings-on-Hudson, NY. (914) 478-4100, naturalvetforpets.com
Everett Mobley, DVM, Kennett, MO. (573) 888-2255, yourpetsbestfriend.com.
Tia Nelson, DVM, Helena, MT. (406) 442-0188, tdbhelena.com
Jeannie Thomason, CVND, Cottonwood, CA. drjeannie.com
Lipomas and Liposarcomas:
- Dogs and Lipomas
- Lipomas in Dogs: Benign Fatty Growths
- Lumps and Bumps on Dogs
- Lipoma and Sebaceous Cysts
- Lipomas in Domestic Animals
- Lumps and Bumps: Lipomas (fatty tumors)
- Lipomas (Fatty Lumps) by Becky Lundgren, DVM
- Not All Soft Lumps are Lipomas!
- Liposarcomas in the Dog and Cat
- Lipoma and Liposarcoma in the Dog: Fatty Tumors
Liposection for lipomas:
- Liposuction For Pets: Procedure Becoming Increasingly Popular (Update July 2014)
- http://onlinelibrary.wiley.com/doi/10.1111/j.1748-5827.2011.01083.x/abstract or http://www.ncbi.nlm.nih.gov/pubmed/21797873
Liposuction for removal of lipomas in 20 dogs, Article first published online: 28 JUL 2011
Small Animal Dermatology
“Intralesional injectio of 10% calcium chloride will cause regression of the lesion, but is not recommend as a treatment because it causes irritation and necrosis.”
Calcium chloride for treatment of subcutaneous lipomas in dogs.
J Am Vet Med Assoc. 1985 Mar 1;186(5):492-4.
“Ten dogs were selected for treatment of SC lipomas (n = 18) with intratumor injection of 10% calcium chloride. At 6-month follow-up, 4 tumors had regressed completely and 14 were less than 50% of their original size. Skin necrosis overlying treated tumors developed in 3 dogs.”
Fine needle aspirate and cancer:
“After numerous studies in the medical literature there is no evidence that an FNA results
in spreading cancer cells or results in any increased risk from the cancer.”
- Does Fine Needle Aspirate Increase Cancer Spread?
- Does the taking of biopsies affect the metastatic potential of tumours? A systematic review of reports on veterinary and human cases and animal models.
Doesn't performing a fine needle aspirate/biopsy make the tumor "angry” and increase the risk of spread? NO. Getting from the primary tumor into the blood stream is only one of many hurdles a tumor cell must overcome to successfully spread. There are probably many circulating tumor cells in the body all the time, but it is only those few tumor cells with the complete genetic program that allow them to survive and grow at a distant site that will be able to successfully spread. Exceptions to this rule are: (I) Some mast cell tumors may become "inflamed" following a fine needle aspirate due to histamine release, although this in no way hastens spread. This is rarely serious and can be treated or prevented with an antihistamine such as Benadryl; (2) Needle aspiration/needle core biopsy of splenic and bladder masses is inadvisable, due to the risk of local tumor dissemination in the abdomen and/or seeding of the biopsy tract. (3) It is important that needle aspirates and biopsies of cutaneous/subcutaneous masses are planned so that the biopsy tract can be incorporated into the definitive surgical excision to prevent recurrence along the tract.
You can contact me if you have any comments, but I regret to say that I can no longer respond to questions about individual dogs. See my Contact page for more information. My name is Mary Straus and you can email me at either or