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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- muhindo bivarton said good work, thank u
- Dr. Nehal rana said Well explained. . Awesome explanation. I thought dat why ans is D not E initially. .
- Deb said Appreciate the information so much!
- Tracey said Excellent explanation, thank you!
- Kristine said Oh. Good question. Sometimes the word “pseudopalisading” is used when there is necrosis...
- Ujwal said What do we meant by pseudopalisading? I got confused by above answer of palisading with example of n...
- Doaa said Great learning site. I hope that you strongly focus on macro and micro photos for illustration. Than...
- Ujwal said Thank You so much for the informations. Really glad.
- Liz said Great site & even more excited to see that you’re local!
- Leandro Zuniga said Nices and helpful explanation, thanks a lot.
- Kristine said Good question! Polarity refers to the orientation of cells. For example, epithelial cells in glands...
- m.hamdy said thanks very much, i want to know the difference between polarity and palisading