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Oncology (General Cancer)/Atrial myxoma misdiagnosis - low grade cardiac sarcoma


QUESTION: Dear Dr. Highly,

We have previously had a conversation about the finding of (possible bi)atrial myxoma and the clinically suspected diagnosis of superior vena cava compression. I am female, and 27 years old.
On Friday,  i  had a cardiac gated MRI to further characterize the mass and to determine the urgency of surgical inervention (which is an issue of debate in my case due to my poor general condition, severe preexisting conditions and severe underweight).
the cardiac MRI now suggests rather a diagnosis of a low grade malignant cardiac sarcoma than a diagnosis of an atrial myxoma, along with superior vena cava compression by tumor. As far as i understand the tumor is  mainly intra-pericardial, attached to the atrium, located between the great vessels there, and partly extending down into the atrium. It also seems that the tumor was posteriorly compressing the thoracic spine which would explain my new onset tingling/thoracic back pain.

My questions are now:
1. what does a low grade sarcoma mean? It is my understanding that its a malignant soft tissue tumor, yet its not that aggressive and grows slower than more aggressive/highly malignant tumors. Is this correct?
What would be a rough prognosis then?

2. how is such a low grade cardiac sarcoma treated? Surgery? Radiotherapy? If surgery is the main therapy - is radiation an option to shrink the tumor before surgery so that surgery may become easier and less extensive?

3. one year ago,  i had a PET /CT done due to the suspected diagnosis if a paraneoplastic phenomenon. (Vasculitis like dermatological/rheumatological/neurological symptoms without evidence of autoimmune disease and unresponsive to steroid therapy). This PET /CT didnt show abnormal uptake except for a low grade increased uptake in the mediastinum. (i think the suv was something like 2.5). Furthermore, uptake was not homogeneous as it would be in the case of thymic hyperplasia.
Due to these inconsistent results the differential diagnosis was thymoma or thymic hyperplasia. I indeed had surgery as the radiologists were unable to exclude thymoma and a thymoma would have been known to frequently cause paraneoplastic syndromes.
However, histology said only b cell hyperplasia. (I do not have myasthenia ).
My question is now: could the uptake (suv 2.5)  have been the result of a possible low grade cardiac sarcoma , especially as the enlarged thymus was covering much of the oericardium?

4. do you know of (cardiac)sarcomas causing a paraneoplastic syndrome ? the immunological clinic seemed to support the diagnosis of myxoma as they are notoriously known for inducing autoimmune symptoms.

5. do low grade cardiac sarcomas metatasize? So far , abdominal/thoracic MRI dont show anything but i am a but worrying about the thoracic back tingling/pain.

Thank so much for your help!


ANSWER: The real danger of heart tumors is that they can shut down cardiac function.  A sarcoma, even low grade, is a little worse than a myxoma, because there would be a higher tendency for it to  return if surgery were done.  Nevertheless, surgery is still the only way to deal with it.  Sarcomas in general are not very radiosensitive, and radiation can damage the heart.  I wouldn't use radiation unless it were a desperation/emergency.  Chemotherapy is not very useful either.
While shrinkage of the tumor may take place in 30-40 percent, it usually isn't much and doesn't last very long.  It's possible that the PET was showing the sarcoma, but if you had an enlarged thymus with b-cell hyperplasia, that could be the whole explanation for the PET findings.  the lower the grade of the tumor, the less intense will be PET uptake.  
Sarcomas generally don't cause the classic paraneoplastic syndromes.  However, some of your symptoms may be related to the sarcoma.  Only way to tell is to get rid of it.  Finally, even low grade sarcomas can metastasize, but I think the history of your back pain suggests that this is due to the effects on the superior vena cava.  
Hope this helps.  

---------- FOLLOW-UP ----------

QUESTION: Thank you so much (and sorry for the misspelling of you name)
1. how much worse is a low grade sarcoma in relation to a myxoma? Is life span decreased? I read pretty different statements in this regard. Some say that even low grade cardiac sarcomas carry a poor prognosis due to frequent local recurrence despite complete removal...?
2. some of the symptoms assumed to be of paraneoplastic origin could be in fact due to skin embolization ( rash/maculapapular skin lesions) and decreased vascular blood flow (raynauds) according to the onco- radiologist.
Is this correct?
3. how long could a low grade sarcoma have been there? I have read some case studies in which patients have had symptoms for years (since growth rate is rather slow for a malignant tumor?)
4. Its my understanding that cardiac MRI suggests a diagnosis of a low grade tumor but the exact hostological subtype and aggressiveness can only be determined by pathological investigation. If thats true - does one have to do biopsy first or just go ahead with surgery? How radical must surgery be ?

Thanks so much.

ANSWER: 1.  Tumors of the heart are very rare.  The most common is the myxoma.  There are several varieties of sarcoma which can occur in the heart.  In my opinion sarcomas are worse than myxomas, and the average person with a sarcoma has a life span of six months.  This is an average and shouldn't be taken seriously in making treatment decisions, because most sarcomas aren't operable at the time of diagnosis.  Indeed sarcomas have a recurrence rate after removal, but that depends on the degree of malignancy, which can only be found by biopsy.  
2.  some of your symptoms may be due to the sarcoma;  I'd not think the rash would, given that rashes from embolization are generally associated with skin necrosis/  the reynauds, however, could be.  
3.  Low grade sarcomas could indeed be there for a long time.  The longer the symptoms before discovery, the more "low grade" it is, and the better the prognosis.
4.  You are right that short of biopsy we can't really say what the histologic subtype is, or indeed, whether the tumor is malignant or not.  Biopsy is probably not a good idea, since it carries risk, would only sample a tiny amount of the tumor (and sarcomas can look different depending what part is sampled) and because regardless of what is there, surgical removal is indicated.  As for how radical, the surgeon wants to get all the tumor, but leave you with a functioning heart.  If the surgeon feels that he can't do this, then you are a candidate for a heart transplant.  
You've got a lot to think about, but please don't hesitate to have the surgery.  

---------- FOLLOW-UP ----------

QUESTION: Thank you so much for your help, i really appreciate it.
I have just talked to the cardiothoracic surgeon who also did my thymectomy last year.

1. He agreed in that he thinks of a sarcoma instead of a myxoma, e.g. because of the location: myxomas would be most often found in the left atrium, sometimes RA or other heart chambers but would never involve or start in the pericardium.
Also, the tumor enhances heretogenously after contrast administration in the MRI, and myxomas very rarely caused SVC syndrome. Is this all correct?

2. he said that only from looking at the MRI images he cant tell for sure if he is able to remove all of the tumor, especially the parts between/wrapped around the great vessels.
He did say , however, that there was still an alternative to the usual open heart surgery before thinking about orthotopic heart transplantation: auto-transplantation, which apparently means complete excirpation of the heart from the thoracic cavity and reinsertion after having removed all tumor material from the heart. Do you know anything about success rates for autotransplantation for cardiac tumors? I would just worry about the immunosuppressive therapy after HTx.

3. he also said that he would guess on the aggressiveness of the tumor before opening me up but still then, there could be false guessings from the outward look. So waiting for pathology was essential.
Apparently, he has seen some cases with malignant cardiac tumors (i am lucky that i got to know him through a former GI surgeon of mine, he is considered one of the best cardiothoracic surgeons in Europe). And sometimes, there were big surprises when he read the pathology report: sometimes, according to histology, the tumor/sarcoma was graded pretty high and considered highly malignant but the clinical picture of the pstient had been rather harmless, with local symptoms having lasted several years (up to 5 years) before. The patient survived without adjuvanf therapy after surgery.
Then, there were cases of appatently less aggressive/low malignant tumors which clinically acted pretty much like high grade tumors, with recurrence, distant metastases etc even some years after successful removal. And he had also seen benign myxomas with a faster growth rate than some sarcomas.
Does this reflect your own experiences?

4. so you wouldnt do adjuvant chemo/radiation therapy after surgery with complete removal? I wouldnt do chemo (i think i wouldnt make it through due to my severe underweight), but radiation wouldnt decrease the risk for recurrence either?

5. Lately, i have been experiencing night sweats. Its not drenching, so i dont worry that much, but sweating is very atypical for me. Due to my severe underweight  i am pretty much cold all the time. When i go to bed i am not feeling warm at all, i am actually feeling cold. Then, in the second half of the night i wake up , and i sweat , but only on my trunk/chest . As i said, its not drenching, but its sweat (not only a feeling of warmth). Could it be related to the tumor?

1. I agree
2.  autotransplantation is indeed a possibility  -- and I sort of included that under my own concept of "heart surgery". It's pretty rare when someone actually has this done.  If the heart has to be taken out of the chest in order to do the operation, it usually means the disease was more extensive than if it could be done with the heart in the chest.  I think you would live through the surgery and recover, but whether all the tumor would be removed would depend on time.  Even if all the visible tumor is removed, the surgeon and the pathologist simply can't look at everything and see microscopic deposits of tumor.  
3.  I agree; a tiny piece of the sarcoma is often not reflective of the degree of malignancy (malignant behavior) of the rest.  And even the microscopic appearance is not a guarantee of how it will behave.
4.  As I said before, I don't think there is a role for adjuvant chemotherapy or radiation therapy if this is a sarcoma.  If you used radiation at a dose that would kill the sarcoma, you would almost certainly destroy the heart.  And chemo never works.
5.  The sweats could be due to the tumor, or related to the fact that you might be in negative nitrogen balance because of the tumor and your underweight state.  Tumors with bits of necrosis ( as this seems to be) can cause the body to sweat.  Again, you won't know until it's out of you.  Hope you do well.  

Oncology (General Cancer)

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Donald Higby, M.D.


I can answer almost all questions related to the treatment and natural course of most kinds of cancer, especially cancers of prostate, colon, lung and breast.


I have been a practicing medical oncologist for 36 years, and have been chief of service at a major medical center for 25 years. I've also done research in cancer treatments.

American Society of Clinical Oncology

New England Journal of Medicine American Journal of Medicine Journal of the American Society of Clinical Oncology Hematology Transfusion Medicine

MD, Stanford University Internal Medicine residency, St. Louis University School of Medicine, St. Louis, MO Medical Oncology Fellowship, Roswell Park Cancer Institute, Buffalo, NY

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