How could I have got myelofibrosis?
If you were previously diagnosed with a myeloproliferative disorder (MPD) such as essential thrombocythemia, polycythemia vera or chronic myelogenous leukemia, your myelofibrosis is reactive and secondary to the pre-existing MPD. If it arose de novo with no prior history of another MPD, no one knows for sure. You might have had a prior undiagnosed myeloproliferative disorder, discovered only after you developed myelofibrosis. It might be likely to be a specific gene abnormality which develops over a period of years.6.