Wednesday, October 8, 2008

It's not a tumour, okay

Lumps that appear on older pets are always alarming because of the possibility that they may be cancerous. That said, one of the most common lumps we see are lipomas, a benign fatty-type mass. They can present a problem by insidiously growing so large they present a mechanical obstruction - hindering an animal's movement. I saw a small patient last week with a large lump behind his forearm that was impeding his mobility. The problem was the lump had become so large (the size of a football on a very small dog) that it would require radical sugery to remove. Associated Professor Geraldine Hunt at the University of Sydney has been pioneering liposuction techniques to remove these lumps in older dogs without removing half of the dog with it. This technique is still in development but it may present a viable alternative to radical surgery in the future (nb it is definitely not cosmestic). Obviously its even better to remove them when they are small. Lipomas can also turn malignant.

Anyway, my Aunty's mature-aged Rottweiler, let's call him B, recently sported two lumps which appeared quickly on his flank and doubled in size within a week. Fine needle aspiration of the lump revealed some pus but it wasn't an abscess. Aggressive masses like this in an older dog are always a concern. She booked him in for surgery to remove the lumps and had them sent away for histopathology (its one thing to have a lump removed but its always helpful to spend the extra money and get it analysed by a pathologist - this tells you what the lump is, if it is cancerous what type of cancer, how aggressive or malignant it is and how it might behave in the future, and whether the surgeon got clean margins). The pathologists identified "necrotising granulomatous steatitis" - nectrotising means dying, granulomatous refers to inflammation and steatitis is inflammation of fat. B had been kicked by a horse and developed a blood clot, which was essentially rotting as it was breaking down. No doubt painful, but surgical removal is curative and his prognosis is great.

The moral of the story is that as a vet it is almost impossible to tell what a lump is unless you remove it and send it to the lab - and the news isn't always terrible.

(There seems to be an unintended equine theme persisting in this blog!)