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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- Kristine said Looks like a naked nucleus to me – and a damaged one, at that. I don’t see any real cyto...
- Christine said What is the large teardrop shaped cell at 2:00? And how did it get that way?
- Kristine said Yes! Exactly! All non-antigen-presenting cells have 6 different types of class II MHC (HLA) molecule...
- daryan said A really helpful and clear explanation. Thank you!
- AMINATU ADAMU said thank u so much for helping me
- Nargis said Thanks a lot.. I am glad that I came across this site of yours
- dr muhammad haroon said Great explanation! Very informative and actually makes sense. Thank you!
- SIMI SADASIVAN said excellent!you teach it as a simple language.more helpful to us.Thank u
- Kristine said So glad you liked it! Thank you!
- Chikaodiri said Wow so simplistic. Thank you Dr. Kristine.
- MMM said Oh boy, I’m so confused with this and your explanation is great! Just now more question: so 6...
- Papa Bear said Thank you so much for clarifying! I really appreciate it!