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.
- Elaine Puricelli said Hello, Thanks for the info on Howell Jolly bodies. I have had these critters consistently since my s...
- Sarkaft said دست خووش… Thsnks alot
- shiru said thankyou thankyou… im surely going to pass my finals. pathology student rocks my world!!!!!!!!
- rajesh said best explanation we can ever get. thank u so much
- Jason said Amazing resource. This and the article on phemphigous vulgerus and bullous phemphigoid difference ar...
- Amanulla said Do people with O blood group also have H antigen?
- vivek said Thanks for sharing
- Raffi said Thank you for your detailed response!
- Kristine said WOW, Luisa, that’s GREAT!!! So happy for you! I would say “had” at this point
- Kristine said Thanks, Venessa Yeah, I know what you mean…sometimes teaching is seen more as an unpleasant t...
- Kristine said Haha that’s hilarious!! I love that
- Kristine said Good question! The little bit of thrombin that has been formed by the extrinsic pathway is the the t...