MYELOFIBROSIS

'Myelofibrosis with myeloid metaplasia', also known as 'agnogenic myeloid metaplasia', 'chronic idiopathic myelofibrosis', and 'primary myelofibrosis',^[1] was first described in 1879 and is currently classified as a myeloproliferative disease caused by the growth and proliferation of an abnormal bone marrow stem cell, resulting in the replacement of the bone marrow with fibrous connective tissue. An eponym for the disease is Heuck-Assmann disease, or Assmann's Disease.

Contents

Presentation

Diagnosis

Treatment

Notes

Presentation

The replacement of the bone marrow tissue reduces the patient's ability to generate new blood cells resulting in progressive anemia. A prime feature is "extramedullary hematopoeisis", i.e. the remaining blood-forming cells migrate to other sites in the body, e.g. the liver or spleen. Patients will typically have an enlarged spleen and liver, (hepatosplenomegaly), and examination of the blood cells will show "teardrop cells". Causes of death include infection, bleeding, organ failure, portal hypertension, and leukemic transformation.

Diagnosis

In order to diagnose myelofibrosis, the following criteria must be fulfilled:

★ (1) no evidence of other myeloproliferative disorder

★ (2) no evidence of secondary bone marrow fibrosis

★ (3) leucoerythroblastic picture on blood film

★ (4) presence of splenomegaly

★ (5) increase fibrotic process in the bone marrow.

Treatment

Typically affecting patients older than 60 years old, it is a chronic and debilitating condition. The median survival for those patients diagnosed after age 60 ranges from 3.5 to 10 years. Currently the only known cure is a bone marrow transplant. The disease progresses very slowly, however, and treated patients can live for five, ten, and even eighteen years after diagnosis. Since the typical patient is older, and the bone marrow replacement treatment is very rigorous, painful and high risk--involving the use of chemotherapy to destroy the patient's existing marrow tissue--the procedure is often not used.
There are other treatments available to reduce the effects of the disease, which are repeated at regular intervals to maintain quality of life for the patient.

Notes

1. Older terms include "myelofibrosis with myeloid metaplasia" and "agnogenic myeloid metaplasia". The World Health Organization utilizes the name "chronic idiopathic myelofibrosis", while the International Working Group on
Myelofibrosis Research and Treatment calls the disease "primary myelofibrosis".