Secondary myelofibrosis – Etiology, Pathogenesis, Investigations and Management

Normal bone marrow
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• Myelofibrosis refers to replacement of normal bone marrow constituents by fibrous tissue
• Secondary myelofibrosis occurs as a result of various pathological processes that involve the bone marrow

Causes of secondary myelofibrosis:

• Neoplastic – infiltration by cancer cells (primary is usually located in breast, lung or prostate)
• Infective – tuberculosis, fungal infections, HIV
• Metabolic – Gaucher’s disease
• Hematological malignancies – chronic myeloid leukemia, multiple myeloma, lymphomas
• Radiation, radiomimetic drugs
• Others – Sarcoidosis,  congenital osteopetrosis

Pathophysiology:

• Marrow contents are replaced by fibrous tissue
• There is extramedullary hematopoiesis in sites like spleen and liver
• Increased number of circulating hematopoietic progenitor cells

Investigations:

• Bone marrow aspiration gives a ‘dry tap’ – no cells are obtained
• Bone marrow biopsy reveals fibrosis of bone marrow
• Peripheral smear
  • anemia – normocytic, normochromic
  • leukoerythroblastosis – blast forms of RBC’s and WBC’s

Management:

• Treat the underlying condition
• Bone marrow transplantation