Multiple Cancers in Dogs


Multiple cancers - can biopsy spread cancer

Question: Dr Mike, I have been browsing your site several times during the last two months and have decided to subscribe because, first, I appreciate what you are doing here. secondly, I have some questions of my own and welcomed the opportunity to ask them of you directly. it may seem as i am writing a book here so please bear with me I will try to be as clear and concise as i can also these questions come "post mortem" so if there are other more pressing needs please feel free to put this on the "back burner"if need be. as these questions are to satisfy my own curiosity and thirst for knowledge. not needed to save a life here goes

I was the proud owner of an exceptional animal, he was a shepherd heeler mix that i adopted when i lived on the island of maui (incidentally if you would like to know more i have built a website for him) Max ( his name) had been very healthy for most of his life he is gone now, but the story goes as follows

earlier this summer Max developed a limp in his right front leg our vet at the time felt it was arthritis and prescribed Rimadyl which was effective for a short interim, but the limp persisted after a radiograph, it was fairly obvious he had osteosarcoma a large tumor on the humerus. we did not biopsy as we had heard this could "turn it on"if it was done improperly. After a lot of research on the web and a lot of it on your site i was convinced he had classic signs of osa and we had him "staged " on june 22nd 2000 at our local vetmed teaching hospital at the University of Illinois at this time there were no visible mets in his lungs, ultrasound revealed nodules on the liver and spleen, and after negative aspirates on three of these nodules the oncologist felt these were not a survival issue he also had what appeared to be mast cell tumors on his skin the oncologist recommended amputation of the leg, excision of the masts at the same time (he was 9 and 1/2 years)so he would have only one anesthesia event and biopsy of the mast's was optional,I opted not to in order to keep costs down, and chemotherapy. we had the leg amputated, and histopathology confirmed osteosarcoma he developed a seroma which pushed him back for chemo finally after the seroma had stabilized and preop blood work indicated he was ready we were two days out from his first round when he stumbled and later that day he had lost color in his mucous membranes after several hours and lots of tests it was determined that he was bleeding out from his spleen, a second ultrasound revealed two masses on his spleen, that were not there when he was staged 6 weeks earlier, abdominocentesis revealed blood and this was not clotting, his white count was extremely high and his hematocrit was dropping alarmingly fast . the preliminary diagnosis was hemangiosarcoma and that one or both of these masses had ruptured presented with the options for a spleenectomy and a transfusion, i realized he would be pushed back even further for chemo and made the hardest decison of my life and let him go. we were heartsick and did not request an autopsy and an autopsy is not an option now. so i realize i may be asking you to guess,

now my questions are,

1. do you feel the diagnoses of hemangiosarcoma was accurate? i have done a lot of research and am comfortable that i did the right thing for max i understand that abdominocentesis which reveals blood in the abdominal cavity which does not clot is a strong indication of this, added to the fact that he had nodules on his spleen when he was staged.

2. is it possible that aspirating these nodules "turned" them on? i understand that hemangio mets quickly and usually takes about the period of time that maxs case did. I was not concerned about these nodules at the time of staging based on the oncologists findings. but , is it possible these were already malignant? even though they showed up as negative?

3. i recall reading somewhere (possibly your site) that there may be a strong connection between mast cell tumors and hemangio is it possible that what we thought were mast"s were actually hemangio? and if this true then do you think that the mast's should have been biopsied when they were excised?

4.i have learned and been reassured that patients with osteosarcoma and hemangio dont respond well to chemotherapy, as when the hemangio became apparent he probably allready had mets elsewhere, is it possible that the masses on his spleen were actually osteo? i have not heard of any cases where osteo metted to the spleen i am under the impression that osteo will met to the lungs in most cases

i am wanting to know if he had three cancers or variations of one or two.

5. is aspirating a tumor or nodule considered to be an invasive procedure? my instructions to the oncologist were clear when max was staged that i did not want any invasive procedures used, as i was concerned about veterinary students "screwing up"

i wonder, had the nodules not been aspirated , if we would have max here today getting ready for his second round? it is obvious that he was "riddled" and we did not have any options but there are some lingering questions , and after reading your clear and detailed explanations to others I welcome your opinion on these concerns, there are several reasons for this i want to be able to help others who might be faced with this and as i have not given up on dog "husbandry" i feel this information could be invaluable to me in the future if you need more information please e-mail me or take a look at the website, i have tried to write it in a documentary

style so it may answer any questions you have that i may not have provided answers to in the above thank you rich

Answer: Richard-

Hemangiosarcomas can develop into a severe problem very rapidly. We did surgery on an older Labrador retriever for bloat (gastric volvulus-dilitation, GDV). It is necessary to visualize and manipulate the spleen to correct this problem and we got a very good look at this dog's spleen. Six weeks later it came into the office with very pale mucous membranes, staggering and very weak. It was easy to palpate a large hemangiosarcoma in the spleen at that time. So this dog went from having a normal appearing spleen to having a large tumor in six weeks. Given this experience, and the high likelihood of hemangiosarcoma producing the clinical signs that you saw, it seems very likely to me that the diagnosis was correct. As you point out, it would be hard to be sure, though.

It is supposed to be very hard to differentiate between hemangiosarcoma and splenic hematomas, which can cause a nodular appearance to the spleen. So it is possible that the nodules were early in hemangiosarcoma and that it was just not possible to detect it.

There is some evidence that certain tumors can be seeded to other areas through fine needle aspirate or other biopsy techniques but I have not seen much information about tumor potentiation or activation as a result of biopsy. In general, the risk of seeding is pretty low with a fine needle aspirate but has definitely been observed with surgical biopsy techniques and with partial removal of tumors. I don't think this was likely to be a factor but can't be certain of that, either.

I am not aware of a strong link between mast cell tumors and hemangiosarcomas, so I hope I didn't say there was one somewhere else on the site. These are both malignant tumors and so a mast cell tumor metastasis to the spleen would have to be considered as a differential for a splenic tumor. Osteosarcomas can metastasize to the spleen, too. You are correct that pulmonary metastasis is much more common, though. You are also correct that the prognosis would be poor in the case of any of these tumors occurring in the spleen.

I have had several patients develop more than one metastatic cancer at the same time, although the one I remember most clearly had lymphoma, mast cell tumors and possibly osteosarcoma (or possibly a spread of the lymphoma to the bone) at the same time. The X-rays looked like osteosarcoma but the dog was well into treatment for lymphoma when that complication occurred and we made no attempt to treat or definitively diagnose the problem.

I think that any biopsy is an invasive procedure but so is drawing blood, so I guess I'd stick with a fine needle or even a Tru-Cut (special cutting needle) biopsy as being "minimally invasive" procedures. I think that almost all veterinarians would agree with that definition and would have been comfortable doing at least the fine needle aspirate procedures with instructions not to do anything invasive.

There is still controversy over whether biopsies like this spread tumors but the majority opinion appears to be that it is possible but that it very rarely occurs. The feeling is that tumor cells have a hard time implanting and are usually handled by the immune system in the biopsy tract. The benefits of knowing what a tumor is outweigh the risks of the procedure in this case, by a wide margin.

I really think that you did about as well as you could have making decisions as the problems with Max unfolded. Sometimes, even the best decision making just doesn't work out well, especially when the odds are stacked against you at the onset, as they were in this case.

Mike Richards, DVM 9/4/2000

Last edited 01/30/05


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...