By Dr. Debbie Marks
Dogs, cats, rabbits, ferrets, birds, and lizards all show up to the clinic with various sized and shaped lumps and bumps. Most lumps may never seem to be of any bother to the animal, but many, astute pet owners are rightfully concerned and want to know what their options are.
Unfortunately, nothing about the size, shape, color, consistency, location, or growth rate is definitively diagnostic for what a lump might be. Yes, benign, fatty tumors (lipomas) and some “cysts” are very common, but some very malignant tumors will look, grow, and feel identically, and are just as common. Far too frequently will I sample a mass that was previously presumed (based either on feel or how long it had been present) to be a lipoma or other innocuous mass to find that it is, indeed, a malignant tumor, slowly spreading for months or years.
Essentially NEVER will I tell an owner that I know what a lump is without some sample of the mass.
Two general options exist to collect a sample for diagnosis; a fine needle aspirate or a tissue biopsy.
Fine needle aspirates use a tiny needle to collect a small sample of cells from the mass. This process is quick, inexpensive, non-invasive, and can usually yield a definitive diagnosis of the mass in question. At the very least, the results of the aspirate should be able to dictate the general course of action insofar as whether to leave the mass alone, to remove the mass surgically, how aggressive to be with surgery (how much tissue surrounding the mass should be removed), and whether to be concerned with nearby or distant spread.
Tissue biopsy, that is, removing all or some of the lump surgically, is more invasive and more expensive, but will nearly always be diagnostic. Removing a benign mass, though, may not be necessary, putting your pet through an avoidable procedure. Furthermore, removing malignant tumors without a pre-operative diagnosis may predispose us to inadvertently leaving microscopic bits of tumor behind, thereby missing a chance for a curative surgery, and also complicating future attempts at therapy. For these reasons I will
usually recommend a fine needle aspirate prior to any mass removal, and certainly prior assuming any mass to be benign.
The sooner you know what a mass is, the sooner you can know whether to write it off or take it off.
Disclaimer: No article, journal, webpage, breeder, or friend of a friend can take the place of personalized, veterinary medical advice. If you have any questions, always consult with your veterinarian.
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