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Ever wondered what that strange lump is on your pet? Read what Veterinarian Elaine McIlhinney has to say.
A common issue that we see in our patients at Mill Road is lumps! Even our exotic patients (rabbits, Guinea pigs, rats, mice, birds etc.) get these! Lumps can be a cause of panic to our clients, especially when they appear suddenly and the animal is unwell or sometimes can be completely hidden and we find them when your pet is at the clinic for an unrelated issue.
‘Google’ is a useful tool but it is not a good idea to do this with lumps!! Veterinary expertise is required to discern the best approach. At the same time, the pet’s health can be assessed and regional lymph nodes can be checked.
Sometimes, a lump can be an abscess forming after a bite or due to a foreign body such as a grass seed. Other times, it may be a benign growth such as a skin tag commonly found in older dogs or a sebaceous cyst which are more common certain breeds such as Shih Tzu’s. Mast cell tumours (MCTs) are a type of tumour commonly found on the skin; these are somewhat unusual in that they do not have a typical appearance and can vary in malignancy. MCTs are easy to rule out or in with cytology. The recommendation is to remove mast cell tumours with good margins.
Cytology involves collecting a sample of the lump using a tiny needle and syringe and expressing the contents onto a slide. In most of our patients this is easy to do conscious with gentle restraint and often dogs eat treats simultaneously and don’t even notice! The sample on the slide is then dried, fixed and stained in our lab. Next we view the slide under the microscope at x100 magnification oil immersion lens. We check to make sure there are no tumour cells or mast cells.
When tumour cells or mast cells are found, it is best to send samples to Gribbles laboratory in Auckland, where a specialist laboratory veterinarian can examine them. The lab will provide a diagnosis or provide a list of potential types of tumour. Then a plan can be made to remove the lump under general anaesthetic.
When a lump is found it is important to ascertain what it is. Lipomas can be common growths in the fatty tissue of older dogs, especially those that are carrying excess weight. Even when we are suspicious that we are feeling a lipoma, the safest approach is to perform cytology on the lump.
In other cases lumps can be causing discomfort to the patient such as a lump on the eyelid rubbing the cornea of the eye. Sometimes lumps that are currently benign can turn malignant with time such as a cystic lump on a cat’s skin. Once a lump has been found and checked it is a good idea to get it checked once or twice a year to make sure it hasn’t changed. Some lumps do not exfoliate well and a sample cannot be taken for cytology; some lumps can only be diagnosed by sending tissue or the lump off to the laboratory for histopathology. Histopathology is where tissue is removed under general anaesthetic, fixed in formalin and then sections are made into multiple slides at the lab. It is useful to do this as follow up for any lump removal to ensure that the lump has been fully removed with margins and to determine the likely prognosis/chance of recurrence.
If your pet has a strange lump that you would like to get checked out, please call us on 09 437 1101!
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