The four main myeloproliferative disorders share several similarities such as a hypercellular marrow, a high white count with a left shift, and splenomegaly. But there are distinct morphologic and clinical differences too; that’s why they have been separated into four distinct entities.
Take chronic myelofibrosis for example. In this disorder, the myeloid cells proliferate like crazy early on. If you looked the blood and bone marrow at this early stage, you’d see a high white count with a left shift, and a hypercellular marrow, features common to all myeloproliferative disorders. But as the disease progresses, the marrow becomes replaced by fibrous tissue. The hematopoietic precursors have nowhere to grow, so they start setting up shop outside the marrow, in places like the liver and spleen. The spleen, in particular, becomes massive – even bigger than it does in the other chronic myeloproliferative disorders.
You can see evidence of the marrow fibrosis and splenomegaly in the blood if you look closely at the red cells. In squeezing through the tight fibrosis in the marrow, and in navigating through a markedly enlarged and cellular spleen, the red cells take on an unusual, “teardrop” shape. You can almost see how they dragged themselves through tight spaces, stretching their poor little bodies into elongated, pinched shapes. Another word for these teardrop cells is dacryocytes. While not specific for chronic myelofibrosis (they can occur in any case of marked splenomegaly or marrow replacement), if they are present in large numbers and the clinical setting is right, teardrop-shaped red cells are strongly suggestive of chronic myelofibrosis. You’d need to do a bone marrow biopsy to be sure, of course.
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- Marina P said Professor Thomas Renne from Sweden and his group conduct research on the topic of FXII, I found it m...
- sachini said Very important this one.thank you
- Jeevanshu Dhawan said That is the most simple explanation I have read till date. Thanks.
- pooja said Great explanation. Thank you
- Sandhya said Kristine, you are a teacher non-pareil !
- Lilah said Thanks looking forward for the bites
- Kristine said Hi Kanopo – it’s okay! Leukemias and lymphomas can be confusing, for sure. To answer you...
- Kristine said There are a million microliters in a liter (1 L = 1,000,000 microliters). So 4,000 cells/microliter...
- VAISHALI said STILL I DONT UNDERSTAND-LOWER NORMAL RANGE IS 4.0 x 103/μL THAT MEANS IN 1uL THERE ARE 4000 CELLS,SO...
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- LILAH said SOOO GOOD