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Pre-fibrotic PMF


I have ET, MPL515L +, had a recent blood smear showing red blood cell count as, teardrop, target cells, and other defective rbc's. Their frequency was rare, but never had this before. My doctor not concerned, but haven't read about this with ET.

I am concerned might be moving to early myelofibrosis. Anyone with a similar experience?

Thanks to all!

4 Replies

Hi i have had this in the past and investigated it. From memory the answer to this requires highly technical knowledge but in very simple form it means immature ie smaller blood cells. I think they are released from the bone marrow before fully formed. They are not as effective as fully formed larger cells but they are not a problem just an indication of how your treatment is effecting the formation of the cells. For me this changed ie they became normal size and years later I saw the comment again. I hope I have got this right and this helps.



Thanks so much for your response, this makes sense, although I only take aspirin. It alarmed, as it was a new result. I will be seeing an MPN specialist soon, just want to stay on top of everything.

We have to be our own advocate, yes?

So glad this resource is here.

Take care.


Hi I have been thinking about your tear drop results while you are only on aspirin. I had these after venesections in the early stages of my 12 year PV experience. I understood the bone marrow was in overdrive due to the confusion it feels when large amounts of blood is lost.

So why are yours like that when only on aspirin? It might be useful to know why this is. It is a highly technical question and needs to balance your blood experience, symptoms and test results. As you say being your own advocate is important. A wait and see needs to be based on sound evidence.

Kind regards



Good Morning,

Thanks again for responding. It is confounding, as I shouldn't have RBC problems with ET. My RBC counts were normal, so the abnormal cells are rare but, what is it indicating? These type of cells are seen with myelofibrosis, and it can't be PV because the MPL mutation is exclusive to PV.

I also recently learned that with ET and the MPL mutation, more likely to convert to PMF, 25-30 percent. So I think I might have pre-fibrotic myelofibrosis.

Time to see an mpn specialist!

Thanks for your interest, take care.


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