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What is Needle Aspiration?

Needle aspiration, also known as fine needle aspiration, is the most commonly used and least invasive diagnostic and biopsy method available. Fine needle aspiration involves using a needle to collect a sample of cells from a mass, lesion, or organ. Fine needle aspiration may also be used to collect a small sample of fluid in conditions where effusion – or fluid build-up – is present. The veterinarian will examine the sample using a microscope immediately after the sample is collected. 

However, any tentative diagnosis made using cytology must be confirmed by histological analysis. This means the sample must be sent to a laboratory and examined by a certified veterinary histologist. Results usually arrive within one to two days of examination.

Needle Aspiration Procedure in Dogs

Needle aspiration is a quick and painless procedure. The approach to needle aspiration will vary based on the location of the condition. Ultrasound guidance is usually required to collect cell and tissue samples from internal organs. Sedatives or anesthesia may be administered to dogs that have lesions in sensitive areas, including the eyes and ears.

  1. The mass or lesion is cleaned.
  2. A fine needle with an empty syringe is inserted into the mass or organ.
  3. Suction is created when the plunger of the syringe is pulled back. This draws cells into the syringe and is known as aspiration. This process may be repeated several times to ensure an adequate sample is collected for examination.
  4. The cellular sample is transferred to a microscope slide and dried.
  5. A specialized dye is used to stain the slide so the cells show up clearly under the microscope.
  6. The veterinarian will then examine the slide under the microscope before sending it to a certified veterinary histology laboratory.
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Efficacy of Needle Aspiration in Dogs

Fine needle aspiration is one of the most effective diagnostic and biopsy methods available today. It is also one of the least invasive diagnostic procedures, and causes virtually no pain for pets. In fact, the needle used for aspiration is typically thinner than needles used for vaccination. However, fine needle aspiration is not 100% effective. The effectiveness of needle aspiration ranges from 90.9% to 97.9%. The effectiveness of fine needle aspiration biopsy is 70% to 80%.

There is a chance that diseased cells will not be collected through fine needle aspiration. This applies particularly to certain types of cancer cells. While fine needle aspiration may help confirm some forms of cancer, other types of cancer cells – notably sarcomas – are more difficult to collect. This occurs because sarcoma cells do not easily exfoliate, or separate from the mass. Tissue biopsy is recommended to confirm a diagnosis of cancer.

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Needle Aspiration Recovery in Dogs

Because it is a diagnostic procedure, dogs will not need to recover from fine needle aspiration. The veterinarian will contact the owner when the histology results come in – usually within one to two days – to determine the best course of treatment. If owners notice any changes in mass size or appearance, they should contact their veterinarian right away.

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Cost of Needle Aspiration in Dogs

The cost of needle aspiration in dogs will vary depending on standards of living and additional treatment and diagnostic costs incurred. Fine needle aspiration is typically an inexpensive procedure which ranges in cost from $25 to $200. These costs may or may not include laboratory fees.

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Dog Needle Aspiration Considerations

Needle aspiration is not recommended for dogs that have oral lesions or masses, since general anesthesia or sedation will be required to obtain a cell sample. In dogs with dermatological masses, all masses should be evaluated using fine needle aspiration. Sometimes, some skin masses can be benign while others are cancerous.

There are very few complications associated with needle aspiration. The main concern is misdiagnosis. However, misdiagnosis is incredibly rare, particularly if the pathologist and veterinarian are highly skilled. If the appearance of the aspirated mass changes significantly after aspiration, re-aspiration may be required.

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Needle Aspiration Prevention in Dogs

Many conditions diagnosed by fine needle aspiration are difficult to prevent. Owners should make sure their dogs attend regular veterinary checkups so that underlying conditions can be diagnosed and treated quickly.

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Needle Aspiration Questions and Advice from Veterinary Professionals

Need pet health advice? Ask a vet

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Dachshund

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Four Years

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Unknown severity

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Lump

My dog has had a lump for the last week and a half. I took him to the vet today and they preformed a fine needle aspiration. The vet said she saw white blood cells which could mean it could be inflammation or limpoma cancer I believe she called it but she was unsure. It’s now a few hours after the appointment and the lump has decreased in size. Is this a good thing? What does this mean? Should I get a second opinion? Does this cancel out the possibility of cancer?

Aug. 18, 2020

Owner

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Dr. Sara O. DVM

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Hello, If it has decreased in size since the appointment especially if it was a very drastic decrease in size this is most likely inflammation and may eventually go away. If it continues to stay the same size or get bigger then I would worry about cancer. If you give your dog a few days you will know if you need to get a second option or if this is just inflammation.

Aug. 18, 2020

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Labradoodle

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Seven Years

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Unknown severity

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Unknown severity

Has Symptoms

Mass Right Leg

Did needle aspiration on my pups mass. Inconclusive it showed fat skin and blood. Vet still not sure what it is. Pathology doesn’t think a new specimen will help. Just want to monitor. I want to biopsy it even though they said it was not in operable place. Any suggestions

July 24, 2020

Owner

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Dr. Michele K. DVM

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Thank you for your question. Unfortunately, the only choices are to do another aspirate, to take a larger surgical biopsy, or to monitor it. It depends on what the outcome will be, if it is not operable, I'm not sure that it makes sense to try to find out what it is necessarily, unless you are considering going to a specialist for surgery, in which case knowing what it is would be extremely helpful. If that is a route that you are wanting to take, it may be best to have a referral to a surgeon, and have a discussion with them on expected outcomes and what the next step might be. I hope that all goes well for your dog.

July 24, 2020

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Lili Mae

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Shih Tzu

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7 Years

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Fair severity

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Fair severity

Has Symptoms

Multiple Lumps Clustered

My dog has a cluster of lumps on her upper left flank. The vet aspirated one of them and said she found a green sludge that came from the lump. She didn’t think it was serious but suggested that they be surgically removed. What would this green sludge be and wouldn’t a test on it be the next step versus surgery?

Aug. 15, 2018

Lili Mae's Owner

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It depends on the type of sludge which came out; testing options can be limited and in this case the only real option may be making a smear on a slide to determine if any particular cells are present but it probably wouldn’t tell us much. I cannot say what the ‘sludge’ is without looking at various properties of it, however the lumps themselves may be due to abscess, cysts or other growths and may need to be surgically removed regardless. Regards Dr Callum Turner DVM

Aug. 15, 2018

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Comet

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Labrador Retriever

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11 Years

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Moderate severity

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Moderate severity

Has Symptoms

Head Swelling
Drooling
Listlessness
Body Movement In Bed

My dog just had an aspiration (his second, the first aspiraiton resulted in the lump by his right ear growing even bigger) but when the vet poked the needle into the lump, it started bleeding out on its own. The vet told me it was because there was more pressure than the last time and that the bleeding would stop. It only stopped for a while after they cauterised the puncture site, but as soon as we got home, droplets of blood have been appearing is there anything I can do at home to help with the clotting or must I go to the vet again? (Also his drool is copious and thick is this a serious problem?)

Aug. 13, 2018

Comet's Owner

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Dr. Michele K. DVM

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There isn't really anything that you can do at home to stop that bleeding other than gentle pressure or a cold compress. Keeping him quiet will decrease his blood pressure and should also help. I hope that your veterinarian is able to determine what the mass is and what to do about it.

Aug. 13, 2018

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Riley

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American Staffordshire Terrier

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10 Years

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Serious severity

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Serious severity

Has Symptoms

Lump On Hock Joint

I had a second fine needle aspiration done on the lump on my dog’s hock joint, due to the first one being inconclusive. The vet told me there were spindle cells present but she can’t say if it’s malignant or not. What’s next? Should I get a biopsy done before opting for surgery to remove the lump? The vet wants to send the slide of the aspirate to a lab and then do surgery, but shouldn’t I get a biopsy done first before excising the lump? Is there a benign condition that would explain a soft growing “lipoma-like” lump with spindle cells or is it most likely cancer? Please help.

June 29, 2018

Riley's Owner

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Dr. Michele K. DVM

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Spindle cells are rarely a good thing - it makes sense to me to have the slide looked at by a pathologist, as they are experts in that field and can say for sure if those are spindle cells or not. If they are, surgery to remove the mass is probably a good idea.

June 29, 2018

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Cooper

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Labrador Retriever

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3 Years

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Fair severity

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Fair severity

Has Symptoms

Mass

A small quarter size mass showed up on my 3 year old labs shoulder/back area, I took him to the vet for an FNA. The doctor said he is unsure if it is a mast cell tumor or lipoma. My baby is scheduled for surgery on Wednesday and I am terrified. How does he not know if this is a mast cell or not? Is he too scared to tell me it’s cancerous? He was so vague and I am worried what we are facing! Please help!

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Eddie

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Border Terrier

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5 Years

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Fair severity

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Fair severity

Has Symptoms

Lump On Back

Found a small lump on dogs spine and our vet did a needle aspiration on it. she tried a couple of times to get a sample to send off. A yellowish substance was obtained. The results were inconclusive so we are having the lump removed and checked. His lump has become bigger since the the aspiration. Could this be due to the procedure as it was done 5 days ago?

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Blu

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Italian Greyhound

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5 Years

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Mild severity

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Mild severity

Has Symptoms

None

I have a 5 year old male italian greyhound. About two or three years ago i noticed he had a pimple like bump on his foreskin. It never grew so i just left it. Last week i noticed him licking a lot so i looked and saw that it was red inflammed and looked like it was kind of popped. I took him to the vet and they did the cytology test and said that multiple mast cells and eosinophills were noted. What does that mean, do you think that i should have it removed? A couple days after it was red and inflammed it returned to normal. Im just wondering if its back to normal do i still get it removes

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Blu

dog-breed-icon

Italian Greyhound

dog-age-icon

5 Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

Has Symptoms

None

I have a 5 year old male italian greyhound. About two or three years ago i noticed he had a pimple like bump on his foreskin. It never grew so i just left it. Last week i noticed him licking a lot so i looked and saw that it was red inflammed and looked like it was kind of popped. I took him to the vet and they did the cytology test and said that multiple mast cells and eosinophills were noted. What does that mean, do you think that i should have it removed? I might add that The bump is now back to normal not red or inflammed.

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Hugo

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Dachshund

dog-age-icon

13 Years

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Moderate severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

Has Symptoms

None

Our Hugo, 13 yr old mini-dachshund has a mass on his spleen. They did fine-needle aspiration. Report says "no overt malignant cells" but that it doesn't mean it isn't cancer. They said if we do splenectomy and there IS cancer, he won't live much longer. Asymptomatic now.

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