C h r o n i c M y e l o f i b r o s i s
General
• Chronic myelofibrosis is a clonal disorder of myeloid cells characterized
by panmyelosis, extramedullary hematopoiesis, and bone marrow fibrosis.
• The most striking abnormalities involve the megakaryocytic cell line.
Clinical Features
Age
• Peak age = late 50s
Symptoms
• LUQ pain/fullness, epigastric pressure (splenomegaly)
• Weakness, fatigue, palpitations (anemia)
• Minority of patients asymptomatic
Signs
• Splenomegaly (massive)
• Pallor, tachycardia (anemia)
Morphology
Blood
• Leukoerythroblastosis
• Poikilocytosis (with prominent teardrop erythrocytes)
• Atypical platelets (large and hypogranular)
Bone marrow
• Early: hypercellular with lots of megakaryocytes
• Later: fibrotic, with very few remaining hematopoietic cells
• In early stages of disease, WBC is increased. In late stages, WBC is
decreased
• Hgb decreased
• Platelet count increased, decreased, or normal
Pathophysiology
• Fibroblasts are benign in this disorder. Why are they so active?
• Fibrosis may be a direct result of megakaryocyte stimulation.
• Fibrosis may alternatively be simply a secondary (desmoplastic) reaction.
Treatment and Prognosis
• Supportive treatment and busulfan or hydroxyurea.
• "Long" course (mean survival = about 5 years).
• Death usually due to marrow failure, consequences of aging, or leukemic
transformation (1% of cases).
