Fine Needle Aspirate (FNA) – Dogs & Cats
Sometimes a lump or swelling appears on your pet and you want to know what it is.
It might be:
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Dermal lump – within the skin layer
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Subcutaneous lump – under the skin layer
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Intra-abdominal lump – in the abdomen
The only way to know with 100% certainty is to remove the lump under general anaesthetic and send it to an external laboratory for histopathology. The pathologist’s report tells us the exact type of lump or tumour, whether it has been completely removed, and the likelihood of it spreading.
A less invasive first step is a Fine Needle Aspirate (FNA). This quick procedure can give us an indication of what the lump may be and how it is likely to behave.
How an FNA is performed:
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The lump is gently secured.
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A fine needle is inserted into its centre.
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Cells are drawn up into the syringe and transferred to a microscope slide.
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The slide is examined under the microscope by your veterinarian.
For example, a benign fatty lump (lipoma) will show large fat droplets and characteristic fat cells.
Other findings may include:
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White blood cells from an infected lump
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Tumour cells, such as mast cell tumours with visible cytoplasmic granules
The lump is secured.
A needle is placed into the centre of the lump.
The microscopic sample is expressed onto a microscope slide.
The slide is examined under the microscope.
The picture above shows a fatty mass called a lipoma. These are benign fatty lumps that grow slowly. The fat produces droplets seen microscopically often with little fat cells on closer examination.
Other results may include
Limitations:
An FNA is not 100% accurate, but it is often a valuable starting point.
Any lump that is rapidly growing, painful, or larger than 5 cm is usually best removed and analysed by a pathologist.
When to book an appointment:
If you find a lump or swelling on your pet — especially one that changes quickly — have it checked promptly by one of our experienced veterinarians.
Make an Appointment with the Vet →
Call us on 9913 7979
Or message us through the website or email reception@pittvets.au
