| Myelofibrosis
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Etiology
Unknown.
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Pathogenesis
The mechanism of
myelofibrosis is unknown, but is believed
to be due to the abnormal proliferation of fibroblasts in
response to cytokines (primarily TGF-beta and PDGF) from
megakaryocytes.,
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Epidemiology
The disease usually affects individuals late in life
(sixth through eighth decade).
Both sexes are equally affected.
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General Gross Description
The bone reveals a firm, homogeneous, tan to white
appearance instead of the normal appearance of red marrow,
flecked with bone spicules.
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General Microscopic Description
Microscopically, the entire marrow space is replaced with
mature collagen and fibroblasts.
Megakaryocytes may be seen even in late stages.
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Clinical Correlation
Clinically, the loss
of marrow function in the bone
stimulates myelopoiesis in extramedullary sites, such as spleen and
liver.
For this reason, the disease is also known as agnogenic
myeloid metaplasia.
Symptoms may be due to the enlargement of the spleen
(a dragging sensation in the left side); or due to the
reduction in red and white cell function.
Sometimes preceded by myelogenous leukemia, or polycythemia
vera; often, however, the cause is unknown.
The prognosis is not good, with relatively few individuals
surviving five years.
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References
Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th edition. Philadelphia, W.B. Saunders, 1994, pp.660.
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| Myelofibrosis
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| Synopsis by: T.V. Rajan M.D. PhD. (T10510M49000)[78]
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