Mass Removal In Pets
Written by Shula Berg BVSc CertAVP(GSAS) GPAdvCert(SASTS) MRCVS
Clinically reviewed by Elizabeth McLennan-Green BVM&S CertAVP(SAM) MRCVS
Table Of Contents
- Overview
- Diagnosis
- Procedure
- Complications
- Outlook
Overview
A mass can refer to any abnormal growth, whether it is considered cancerous or not. For the purposes of this information, mass is used to refer to growths on the external body, either in the skin (known as cutaneous), or sitting in the layers just under the skin (known as sub-cutaneous).
Surgery to remove a mass can be performed to diagnose or treat; this may be because a mass is cancerous, but may also be to remove a benign mass that is problematic due to its size or location. The size, location and type of mass will dictate the extent of surgery required.
Diagnosis
In an ideal world, we would always know what a mass is prior to removing it. This is because, in the case of cancerous growths, we must remove a margin of healthy tissue around the mass to give the best chance that all cancerous cells are removed. Margins should generally be 1-3cm wide, depending on the mass, so this can make the surgery quite extensive - it is important to be sure this is necessary. Knowing what the mass is also allows us to be sure that surgery is the best way to achieve a cure; some masses are aggressive and we should check for spread around the body (known as metastases) before rushing to surgery.
The simplest method for diagnosis is a fine needle aspirate (FNA), which involves taking some cells from the mass with a small needle. Often, the lab will look at these cells and give us a good idea of what we are dealing with. Some masses don’t exfoliate cells easily, and can give a negative or inconclusive FNA. In this case, a surgical biopsy may be required.
Occasionally, if a mass is very small and in a straightforward area of the body, we may remove the mass as both diagnosis and treatment. In this case, we remove a margin of healthy tissue, but have to accept that there is a risk these margins weren’t big enough if the lump is not what we were expecting.
Procedure
Mass removals are performed under anaesthesia rather than sedation. The area around the mass will be clipped to remove hair, and cleaned to make it sterile. Depending on the size and location of the surgery, wounds are sutured using dissolvable or removable sutures, or stapled. A dressing may be applied to cover the wound.
In the case of large mass removals, reconstructive surgery may be required to close the defect left behind. This involves moving flaps of skin from one area to another, to close the wound without tension. If it is likely that major reconstructive surgery will be required your vet will discuss this before surgery.
Once the mass is removed, it is placed into formalin preservative and sent to an external laboratory. Here, the mass is processed and examined under a high power microscope. This identifies or confirms the type of mass, and allows assessment of the margins to see if they are clear. The lab sends a report back to your vet, who will call to discuss the results with you typically 5-10 days after surgery.
Complications
The main complication of mass removals are problems during healing. All wounds have the potential to become infected, swollen, or fail to heal properly. The risk is increased if the patient interferes with the wound, the wound is very large, or the surgical site is in a high movement location such as the armpit, face or foot. Rarely, if a wound heals poorly, repeat surgery or management of the site as an open wound with dressings may be required.
Complications such as recurrence of the mass can occur if insufficient margins were taken at the initial surgery. This risk is significantly lowered by appropriate diagnostics prior to the procedure, and proper planning of the surgery itself.
Prognosis
For the majority of patients undergoing straightforward mass removals, the prognosis is excellent with complete recovery very likely. Occasionally, surgery does not achieve cure of a cancerous mass either because the mass is more extensive than initially understood, or because the mass has already spread elsewhere in the body. In this instance, further surgery, chemotherapy, or radiotherapy may need to be considered. This is uncommon however, and your vet will advise you.
Page last reviewed: 10th October 2024
Next review due: 10th October 2026
Disclaimer
Please note that the content made available on this webpage is for general information purposes only. Whilst we try to ensure that at the time of writing all material is up to date and reflects industry standards, we make no representation, warranties or guarantees that the information made available is up to date, accurate or complete. Any reliance placed by yourselves is done so at your own risk.