My dog has osteosarcoma. Is there any chance it's not cancer?

Osteomyelitis and osteosarcoma can look similar, but there are some distinct characteristics that can be seen on x-rays. The image you provided is very blurry, but I do see the lesion and it does look more suspicious of an osteosarcoma. This is not only because of the location (the knee is a common location for osteosarcoma), but also the fact that it is solitary and has not crossed the joint. However, a biopsy and histopathology is the only way to definitively diagnose the condition. Osteosarcoma is unfortunately a rather severe form of cancer that tends to spread quickly and cause a great deal of pain. If Ben is in good spirits though, then I would not advise euthanasia until he doesn't seem happy anymore. Considering that you are interested in more diagnostics and potentially treatment (there are treatment options for osteosarcoma), I recommend you ask your vet about this, or seek a second opinion. I hope that helps and I'm really sorry to hear about poor Ben.

Thanks for using Petco Pet Education Center, formerly Petcoach! The fact that these biopsies have come back inconclusive does not mean that this is not cancer. Unfortunately, this is very likely an aggressive form of cancer. After seeing these images, my main concern is that this is possibly a tumor arising from one of the ribs or sternebrae such as osteosarcoma for instance. In one of the images I see that there is likely pulmonary nodules which are most likely due to metastasis or spread of this cancer. It is hard for me to advice further without being able to look at more images or know more about the case. I would encourage you to check in again with them as another biopsy could be performed. Also, if there is truly already signs of metastasis, the treatment options and prognosis are also limited. I would mention to them the possibility of being referred to a veterinary oncologist who can look at the case with more details and advice further. I really hope they can help you and your boy!

Osteosarcoma can’t be totally diagnosed by an X-ray, and this doesn’t look definitive to me. I recommend taking him to an orthopedic specialist for a second opinion, and they can take another X-ray to compare with this. If it’s bone cancer the moth eaten area will probably be larger or more defined. They can also do a bone biopsy to confirm the diagnosis. He could be lame from a shoulder problem, or even pain radiating down his leg from a disc in his neck. Hopefully he is on pain medication. In my opinion the next step to be sure of the diagnosis would be to get an exam with a specialist. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Riot.

I'm so sorry for Maggie's troubles. Unfortunately there is no way to differentiate between cancer, infection, or fungal disease in bones by x-ray alone. Maggie likely needs a a biopsy of the bone to determine what it is. Other diagnostic testing such as radiographs are ultrasounds of other parts of her body to assess for disease, full bloodwork can potentially give your veterinarian more clues as to what this may be. But for a definitive diagnosis biopsy and potentially culture of the bone may be necessary. Best of luck to Maggie and you; thank you for using Petco Pet Education Center, formerly Petcoach.

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!

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! I am so sorry about Chunk's diagnosis! This is a terrible situation! If Chunk is having such a hard time now, it will likely be the same if the rear leg was amputated. Amputation is just palliative unfortunately, meaning it buys you and the pet time. Most bone cancers have microscopically spread by the time they are diagnosed. If Chunk's tumor is a fibroscarcoma then it is slower to spread and he could get more good time if he loses weight and is able to learn how to get around with 3 legs. So, if you are not ready to give up or give in to the situation, ask to have a biopsy done of the tumor so you know what cancer you are dealing with. If it is a fibroscarcoma then amputate and deal with losing the weight afterwards. If it is osteosarcoma then I think putting him down is fair. I am again very sorry that this is happening to you and Chunk. He is too young!

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear that Kan is having a problem. This could be tricky but the next step would be a CT scan or MRI Scan. Not sure if ultrasound would be helpful but maybe. A fine needle biopsy or aspirate of the mass or a surgical biopsy would hopefully be able to obtain some tissue from the mass to determine what it is. I cannot make out much on the xrays due to the quality over the internet. Possibilities of a mass always fall into some broad categories including an abscess (pus filled pocket from infection), a granuloma or collection of inflammatory cells), a seroma of fluid fulled sac, a hematoma or pocket of blood, or a tumor which could be benign (not cancer) or malignant (cancer). Kan is very young to have a tumor but it must be on the differential list. What else could it be? A very congested lung lobe from multiple things, a lung lobe torsion where a lobe of the lung turns on it's axis and is out of place, an area of calcification, etc. I hope this helps and I hope Kan does really well for you. I'm hoping for the best for you two.