Did my dog's lipoma become a mast cell tumor, or was it misdiagnosed?

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! It depends on the Vet's experience with reading cytology. Most Vets send out their cytology samples to a specialist who is trained to read them. Mast cell tumors have a classic look and tend to be one of the easier tumors to diagnose. You could ask your Vet to send the slides out since that only takes 1-2 days to get them back but sometimes aspirates do not get you an answer. I know you have surgery set up and a biopsy planned. That is the best thing for Precious, to get the mass off and know what it is. It has a high chance of being benign. It is a good thing it hasn't grown much. I wish you the best!

Needle aspiration of lipomas typically yields identifiable fat so i agree with your family vet that it is concerning to not have any material recovered with the needle aspirate. We always start with needle aspiration as it is non invasive with quick results but some masses are harder to diagnose with this test. This typically occurs if the mass is firmer in nature. Going to see a specialist can be helpful as we can sometimes use other techniques such as ultrasound to obtain samples with needle aspiration to try to avoid biopsy. But ultimately biopsy may be necessary for some masses. I hope this helps and thank you for using Petco Pet Education Center, formerly Petcoach!

Very small masses can be tricky to get enough of the needle in the mass without going through it. This area of the body can be tricky to get enough margins due to the lack of tissue before you hit bone, and the movement in the joints makes closure difficult. It could be any number of soft tissue masses, including a wart, mast cell tumor, squamous cell carcinoma, etc. If your vet cannot get enough cells for diagnosis with a fine needle aspirate, simply taking a surgical biopsy without removing the entire mass is an option. When we do bloodwork prior to anesthesia, we are checking the liver and kidney values are normal, no anemia or signs of infection, adequate protein levels, etc. we just want to be aware of any issues inside the body to be able to adjust anesthetic protocols.

I'm sorry for your baby going through this! Unfortunately lymphoma requires chemotherapy. Mast cell tumors if completely removed may not require any further treatment. Therefore it is very important to know where the mass removed was lymphoma or not. I would recommend proceeding with the special staining needed to get that answer. If it is lymphoma and chemotherapy is not done most dogs do not survive longer than 30 to 45 days. That is another reason why it is important to get an accurate diagnosis as early as possible.

Hello and welcome to Petco Pet Education Center, formerly Petcoach. I am sorry that Max has a lump. FNA (Fine needle aspirate) is the name of the procedure your vet performed. Some types of cancers, including Mast Cell Tumors, will exfoliate (give off) a lot of cells when this procedure is performed, and have a very classic appearance under the microscope. Therefore yes, this is a proper procedure and diagnostic test. I would recommend that you chat with your vet about staging (looking to see if the cancer has spread to other locations of the body- usually using ultrasound and chest x-rays), and if it has not, have the tumor removed. Ensure you chat with your vet about if they are comfortable doing the surgery to get proper margins (3cm diameter and 3 facial planes) or if a surgical specialist is required. This will depend on the location of the mass. Best of luck with Max, hopefully it is a low grade and will be cured with surgery!

Hello, and thanks for using Petco Pet Education Center, formerly Petcoach. A needle aspirate is the standard way to get an initial "suspected" diagnosis on a lump, but there are limitations to what a needle sample can tell us. If the cells in the needle sample appear worrisome, then the next diagnostic step is to send in a biopsy (surgical "chunk") of the tumor, or to remove the tumor itself and send the whole thing in to the lab for analysis. So, was removal of the ear necessary? I can't say, I don't know enough about the location or size of the mass. I didn't see the slide from the initial needle aspirate. But if the needle aspirate looked worrisome, and the next step is to remove the tumor or cut a piece of the tumor off, then removing that piece of the ear may have been the only way to find out for sure what the tumor was, and whether surgical removal was curative. Rather than regretting in hindsight that the surgery was done because the histopathology report came back as a histiocytoma, I would be focusing on the good news that Tate doesn't have a malignant mast cell tumor. And removal and lab analysis of the tumor was the only way you could have gotten that news. Hope this helps!

Thanks for using Petco Pet Education Center, formerly Petcoach! Possibilities include mast cell tumor, soft tissue sarcoma, plasmacytoma, carcinoma, something of a benign origin, among many others. It should be something similar or the same as the FNA. Ultimately, the biopsy is what actually provides the definitive diagnosis. Feel free to contact us back once the results are available and we can try to guide you going forward the best we can. Let's keep our fingers crossed that it is something benign. Good luck and have a great day!