No BMB for me, not even mentioned yet from my oncologist. My blood test showed ET with 2 mutations.

Just had my 3rd one done last week. In combination with a full blood panel, it's the only way my MPN specialist can evaluate the the progression (or not) of my ET. It's not a pleasant procedure, but one that must be done, unfortunately.

I had a bone marrow biopsy done in February. My first one. Im an RN and I have assisted Dr’s in this procedure and so insisted that I have it done with IV sedation! The BM showed +ET and also that I do not have any fibrosis

Dear Cindy2,

A bone marrow biopsy is a standard for diagnosing essential thrombocythemia and primary myelofibrosis, and even for polycythemia vera.
A responsible hematologist will never put a diagnosis without the bone marrow biopsy.
Patients with primary myelofibrosis were misdiagnosed as ET because there was no bone marrow biopsy performed at the moment of diagnosis.

"The WHO diagnostic criteria for ETT are as follows [8]. The diagnosis is made if all 4 major criteria are met or the first 3 major criteria and the minor ones are satisfied.

MAJOR CRITERIA

1. Platelet count greater than or equal to 450,000/microliter.

2. The bone marrow biopsy shows proliferation, mainly of the megakaryocytic lineage, with an increase in the number of enlarged, mature megakaryocytes with hyper loculated nuclei. No significant increase or left shift in neutrophil granulopoiesis or erythropoiesis is present, and there is very rarely a minor increase in reticulin fibers.

3. The presentation does not meet WHO criteria for BCRABL1 + CML, PCV, myelofibrosis, MDS, or other myeloid neoplasms.

4. + JAK2, CALR, or MPL.

MINOR CRITERIA; there is a presence of a clonal marker or absence of evidence of reactive thrombocytosis."

https://www.ncbi.nlm.nih.gov/books/NBK539709/

Best regards,
Tatiana

Essential Thrombocytosis

https://www.ncbi.nlm.nih.gov/books/NBK539709/

Diagnosis made after 2016 should always include a bone marrow biopsy.
The 2016 WHO classification and diagnostic criteria for myeloproliferative neoplasms always includes a bone marrow biopsy to distinguish between ET/PV masking as ET and PMF.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC58...

There is no other way to know other than a bone marrow biopsy, because PMF has a pre-fibrotic stage that can mimic ET, from what I could read.
"Prefibrotic PMF (Pre-PMF), a disease state that mimics ET but shows additional abnormalities in the granulocytic lineage, has a risk of progressing to overt PMF or AML in 15.2% or 4.7%, respectively [16,17]."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC87...

If there are significant changes in the blood tests results or symptoms that indicate disease progression, then a new bone marrow biopsy might be needed.
Depending on age, mutation, symptoms, family history, treatment, some doctors might suggest bone marrow biopsy at specific intervals to check on progression.

Best regards,
Tatiana