Fibrosarcomas Mass in a Feline


By: Dr. Alexis Gullett from Animal Medical Center

Julius is an 11 year-old male neutered Persian cat who presented for a large lump on his left shoulder. The owners had just noticed it the night before, but could not pinpoint a date when it had not been there, so it may have been present much longer than that. He was doing well at home otheriwse, except for some nasal discharge and an ear infection. Julius was not up-to-date on vaccines, and in fact the owners were unsure if he had ever had any but thought perhaps he may have as a kitten. After some discussion, it was decided to aspirate the mass to determine what it was. A small needle was inserted into the mass numerous times and anything that was contained within the needle was put onto a slide and sent to a pathologist. The ear infection and the upper respiratory infection were both treated with the appropriate medications. A few days after the initial appointment, the mass was determined to be spindle cell proliferation. The pathologist could not say for sure whether it was cancerous based on the slides that were sent in, but anything with spindle cells is worrisome, as many cancers have cells of this sort. Therefore, removal of the mass and more intensive pathology call histopathology was recommended, and the owner agreed.

Julius came into the hospital later that week to have the mass removed, and it was explained that we would remove as much as we could, but there was no guarantee we would be able to remove the entire thing. After shaving the area for surgery it was determined that the mass was much larger and more involved than originally planned. It was located under several layers of muscle, and unfortunately was connected to the caudal edge of the scapula. After much deliberation, it was decided to take as much of the mass as possible, since to remove everything that could be seen would require removing part if not all of the scapula which would most likely leave Julius with very limited movement of that leg, if any at all. The area was sutured closed, and the mass was sent to the lab for further analysis. Julius was treated with pain medications and antibiotics to keep him comfortable after surgery. He did have a few days of discomfort and refused to eat the first few days after surgery, but with attentive owners and good aftercare, he felt better and was back to normal soon after.

Julius' mass was determined to be a fibrosarcoma, intermediate to high grade. The prognosis for this cancer is guarded, with 25% metastasizing (spreading to other areas) and 40% recurring within 90 days after surgery. Options at this point included further surgery to remove part of the scapula, an oncology consult to discuss a chemotherapy and radiation schedule, or palliative care to keep him comfortable. It was decided at this point to monitor him closely for recurrence. Even after the mass recurs, if it does, quality of life can be quite high until there is respiratory distress from metastasis to the lungs, or if Julius has pain or limping from the position of the mass. While some day a decision will need to be made about his quality of life, for now Julius is happily presiding over his household and keeping his owners entertained.

A word about fibrosarcomas - Many people with cats believe that vaccines themselves will cause their cats to get this particular type of cancer. While it is true that cats are more likely to form fibrosarcomas where vaccines have been administered, this is truly very rare. Many many cats are vaccinated every day, and only a very small percentage - between 0.1-0.01% - will ever develop a tumor. It may also be associated with other injections, but this doesn't mean that we should stop giving cats injections completely. Rather, it means that owners and veterinarians need to work together to determine exactly what vaccines and medications are right for each individual cat.