This marrow section shows the marrow cavity replaced by fibrous tissue composed of reticulin fibers and collagen. When this fibrosis is due to a primary hematologic process, it is called myelofibrosis. When the fibrosis is secondary to a tumor or a granulomatous process, it is called myelophthisis. Diagnosis While the clinical picture described above is characteristic of chronic IMF, all of the clinical features described can also be observed in PV or CML. Massive splenomegaly commonly masks erythrocytosis in PV, and reports of intraabdominal thromboses in chronic IMF most likely represent instances of unrecognized PV. . | Chapter 103. Polycythemia Vera and Other Myeloproliferative Diseases Part 6 Figure 103-2 S uk i Fluí as. K tp r Di k ur H ld í Hujjtr 0G long C L. iimtf JL Loictko Ji Hicflr ir r Amc ht4j Jnènn iï Mdirop . 17th Editioni hbtpi y vv. Copyright ö TH Httl3r ii-Hll CompiflUf. Inc. All right - 4Mii. 4. This marrow section shows the marrow cavity replaced by fibrous tissue composed of reticulin fibers and collagen. When this fibrosis is due to a primary hematologic process it is called myelofibrosis. When the fibrosis is secondary to a tumor or a granulomatous process it is called myelophthisis. Diagnosis While the clinical picture described above is characteristic of chronic IMF all of the clinical features described can also be observed in PV or CML. Massive splenomegaly commonly masks erythrocytosis in PV and reports of intraabdominal thromboses in chronic IMF most likely represent instances of unrecognized PV. In some patients with chronic IMF erythrocytosis has developed during the course of the disease. Furthermore since many other disorders have features that overlap with chronic IMF but respond to distinctly different therapies the diagnosis of chronic IMF is one of exclusion which requires that the disorders listed in Table 103-3 be ruled out. A diagnostic algorithm has been proposed but does not distinguish one disease causing myeloid metaplasia from another. The presence of teardrop-shaped red cells nucleated red cells myelocytes and promyelocytes establishes the presence of extramedullary hematopoiesis while the presence of leukocytosis thrombocytosis with large and bizarre platelets and circulating myelocytes suggests the presence of a myeloproliferative disorder as opposed to a secondary form of myelofibrosis Table 103-3 . Marrow is usually not aspirable due to increased marrow reticulin but marrow biopsy will reveal a hypercellular marrow with trilineage hyperplasia and in particular increased numbers of megakaryocytes in clusters and .
