My chihuahua has a marble-sized lump on its back leg. What is it?

Hello. A knot in the leg of a Chihuahua is unlikely and if it is behind the 'knee' then it is likely his lymph node. If it is larger than 1cmx1cm I would have it checked by a veterinarian. It may just be his normal lymph node however if it isn't sore or tender. Enlarged lymph nodes can be due to infection, or cancer. Due to his age it is much less likely to be cancer.

This lump under Behr's skin is most likely something benign like a cyst or lipoma, however there is a small chance it could be something cancerous. At such a young age cancer is unlikely but not impossible. If the growth doesn't go away within a few days or it gets larger it would be a good idea to have Behr examined by a veterinarian. If necessary a small needle aspirate can be taken from the lump and looked at under the microscope to determine if it should be removed surgically. Thanks for using Petco Pet Education Center, formerly Petcoach and I hope the small lump ends up being a benign growth!

Thank you for your question. A swelling like this could be a couple of things. If Blue does not appear painful and is not limping, this may just be a hygroma, which is just a fluid filled swelling from laying on the hard ground. If this is the case, I would simply recommend soft bedding, and try to keep him from laying directly on the hard floor, and it should improve over 2-3 weeks. If it is painful to the touch, hot, or if Blue is limping, this could be an infection and he should be seen by your veterinarian as soon as you can get him in. Thank you for using Petco Pet Education Center, formerly Petcoach.

Thank you for providing a picture of Mia's lump! It could be a benign tumor, a cyst, or a malignant tumor. Unfortunately in a senior dog, there is always a chance it could be malignant. Any suspicious lumps should be examined by the vet. The vet can perform a test called a fine needle aspirate on it. To do this, the vet sticks a small needle into the lump to get a sample of it's cells, and examines the cells on a slide under a microscope. It's usually painless to the animal, and relatively quick to perform. I would take her into the vet in the next couple of days to have this lump examined and diagnosed so it can be treated as needed. Good luck, I hope this helps!

Hi there and thank you for using Pet Coach! From what you have detailed in your description and the picture you have provided, I would recommend getting her seen by her regular vet sooner rather than later. If she is dealing with a protein / fluid imbalance in her body, this could be causing fluid accumulation in various areas of the body. If something is causing lymph fluid to accumulate in the leg, I would want that also examined sooner rather than later. It does not sound like an injury since she is not painful and given that you are describing it as a sac of fluid, I would want her examined and have this looked at by a vet soon. Blood work is something I would strongly recommend to ensure she does not have any systemic changes that could be leading to this. I hope this helps! Please do not hesitate to contact me with any other questions / concerns you may have. I am also available by phone or text consultation if you would like to talk more about Leah. Please remember to rate this post as helpful or not. Thank you!

Hello. Louie is very young to develop any masses, but it is possible. It is also possible that he injured the joint & this is joint fluid collecting under the skin. The most likely possibility is this is a hygroma. What has probably happened is Louie was resting on a fairly hard surface & the pressure of his weight has created tissue damage over the elbow bones. A fluid pocket forms as the body tries to produce its own cushioning. I do encourage you to have your veterinarian examine this, but do change his bedding to something much softer & pliant, as the hygroma may simply begin to resolve on its own over the next 2-3 weeks. Thanks for using Petco Pet Education Center, formerly Petcoach.

This could be a local site of inflammation from an insect bite or sting. This would especially make sense if it popped up within a day and was irritating/itchy to Pasta. It could also be a small skin tumor, which would be more concerning. I would recommend monitoring it for the about a week to see if it goes away. It the lump persists or becomes larger you should take Pasta to your vet to have it checked out. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach. Best of luck.