Primary Myelofibrosis (PMF)
Clinical signs
- proliferation, especially of the magakaryocytic and granulocytic lineages, associated with fibrosis
- 2 stages:
- pre-fibrotic/cellular
- fibrotic
- early symptoms are non-secific, in later stages symptoms include anemia, organomegaly,
subfebrile temperatures, fatigue, weight loss
- prognosis: median survival time is approx. 3 – 7 years for patients diagnosed
in the fibrotic stage and approx. 10 – 15
years for patients diagnosed during the early pre-fibrotic stage, 5 – 30% of patients develop AML
Histology
- pre-fibrotic stage: hypercellular bone marrow, clusters of increased numbers of large megakaryocytes
with hyperlobated nuclei, dysplastic megakaryocytes, a relative increase in granulopoiesis
(M : E ratio is approx. 5 : 1), none or only slight fibrosis (MF-0 or MF-1)
- fibrotic stage: extensive fibrosis of the bone marrow (MF-2 nebo MF-3)
with residual hematopoiesis, clusters of dysplastic megakaryocytes,
dilatated sinuses with hematopoietic cells, osteosclerosis,
extramedullar hematopoiesis