Myelofibrosis Flashcards
Define
Hyperplasia of megakaryocytes which produce platelet derived growth factor → leading to intense marrow fibrosis and myeloid metaplasia
Disorder of haematopoietic stem cells characterised by progressing marrow fibrosis in association with extramedullary haematopoiesis and splenomegaly
Cause
Primary stem cell defect is UNKNOWN
It results in increased numbers of abnormal megakaryocytes with stromal proliferation secondary to growth factors released by megakaryocytes
30% of patients have a previous history of polycythaemia rubra vera or essential thrombocythaemia (overproduction of platelets by the bone marrow)
Epidemiology
RARE
0.4/100 000 annually
Peak onset 50-70 years
Symptoms
Can be asymptomatic and diagnosed after abnormal FBC finding
Hypermetabolic symptoms – night sweats, fever,
↓weight, anorexia
Pruritus
More rarely: abdominal discomfort (LUQ pain) and indigestion due to splenomegaly
BM failure (infections, bleedings, ↓Hb, anaemia)
Signs
SPLENOMEGALY
Hepatomegaly (present in 50-60%)
Investigations
Bloods
FBC
- Initially variable Hb, WCC and platelets
- Later stages –> anaemia, leukopaenia, thrombocytopaenia
LFTs - abnormal
Blood Film
- Leucoerythroblastic changes (red and white cell precursors in the peripheral blood)
- ‘Tear drop’ poikilocyte red cells
Bone Marrow Aspirate or Biopsy
- Aspiration usually unsuccessful - ‘dry tap’ (due to fibrosis)
- Trephine biopsy shows fibrotic hypercellular marrow, with dense reticulin fibres on silver staining
