Hello, my name is***** and I have over 20 years of experience as a veterinarian. I understand your concern about an enlarged mammary gland that is slowly getting bigger and seems uncomfortable for your pup since she won't let you examine it.Is she spayed now? If yes was she spayed before or after her first heat cycle
?If she's not spayed when was her last heat cycle?Where exactly is this lump located?Is it under the skin and freely moveable or well attached?How long has it been present?If she has had a recent heat cycle she may have suffered a false pregnancy
, which can lead to enlarged mammary glands, milk production and sometimes secondary mastitis. If the swelling seems very red and painful and she is running a fever then mastitis is possible. If she is licking
I would not let her lick. The more she licks the longer she will lactate, as milk is produced on demand. You should put an elizabethan (lampshade) collar on her so she cannot reach to lick.To ease inflammation you can put a poultice of used green tea bags or wilted cabbage leaves that have been soaked in cool water on her mammary chain for 10-20 minutes several times a day.In most cases though mastitis needs oral, systemic antibiotics to clear.If she is not spayed, or went through several heats before being spayed this may be a mammary tumor. These are usually painful, but they can be if there is a secondary infection.The good news is that if she was spayed before her first heat cycle then the chances of this being mammary cancer are almost 0%.If it is toward her back legs
, near the crease where her inner rear leg meets her body this could be a lymph node.Lymph nodes enlarge for lots of reasons including inflammation, infection, trauma, and unfortunately cancer.Here is a diagram of where an inguinal lymph node is located that may help you:http://t1.gstatic.com/images?q=tbn:ANd9GcT2E6ePk8LPeglqMHTpDBfma-x12U_fHJ5Qbr-NF_64-EjyA7ToAnother possibility is that this is a lipoma or fatty tumor, but those should not grow quickly, nor be painful.Ideally your girl needs to see her veterinarian. If she has had a recent heat cycle with a false pregnancy then you can try treating her for mastitis, but most of the time unless it is caught very early that isn't successful. If she isn't improving or if she hasn't had a recent heat or false pregnancy then a veterinary visit is in order. Your veterinarian can examine her and put a needle into this lump, draw off some cells and look at them under the microscope.This is called a fine needle aspirate and that would give you some answers relatively inexpensively.You might also feel around her body and see if any lymph nodes are palpable.In most normal dogs lymph nodes aren't palpable or are very small.Here's another diagram to see where the other nodes are located:http://t2.gstatic.com/images?q=tbn:ANd9GcQ8ng4GVINlQdMAWcrPYQBkrHlXhYQKPUL-CX7vdg7NZnHaqTgj Please let me know if you have any further questions.