extramedullary hematopoiesis


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hematopoiesis

 [he″mah-to-poi-e´sis]
the formation and development of blood cells. In the embryo and fetus it takes place in a variety of sites including the liver, spleen, thymus, lymph nodes, and bone marrow; from birth throughout the rest of life it is mainly in the bone marrow with a small amount occurring in lymph nodes. Called also hematogenesis, hemogenesis, and hemopoiesis.
extramedullary hematopoiesis the formation and development of blood cells outside the bone marrow, as in the spleen, liver, and lymph nodes.

extramedullary hematopoiesis

The production of blood cells in tissues other than bone marrow, e.g., in the liver or spleen. It occurs in severe or chronic anemias and other diseases that affect blood cell formation. Synonym: myeloid metaplasia
See also: hematopoiesis

extramedullary

situated or occurring outside any of the medullas including the medulla oblongata and the medullary cavities of the bones.

extramedullary hematopoiesis
see extramedullary hematopoiesis.

hematopoiesis

the formation and development of blood cells, usually taking place in the bone marrow.

cyclic hematopoiesis of collies
see canine cyclic hematopoiesis.
hematopoiesis depression
a significant finding in cases of endotoxemia.
extramedullary hematopoiesis
the formation of and development of blood cells outside the bone marrow, as in the spleen, liver and lymph nodes.
fetal hematopoiesis
in embryogenesis migration of stem cells from the yolk sac blood islands sets up hematopoiesis in thymus, lymph nodes, liver and spleen. When fetal bone develops a marrow cavity hematopoiesis is similarly established. At birth hematopoiesis is largely medullary.
regenerative hematopoiesis
increased hematopoietic activity in response to a need for more cells; indicated by the presence of a higher than normal proportion of immature forms in the peripheral blood.
References in periodicals archive ?
Massive hemothorax due to intrathoracic extramedullary hematopoiesis in a patient with thalassemia intermedia.
Sonographic features of adrenal extramedullary hematopoiesis.
Extramedullary hematopoiesis (EMH) occurs in various disorders and is most commonly seen in sickle cell anemia, thalassemia, hereditary spherocytosis, polycythemia rubra vera, and especially in myelofibrosis.
Hypothesis: splenic filtration and the pathogenesis of extramedullary hematopoiesis in agnogenic myeloid metaplasia.
6] The atypical growth of the bone hinders with medullary hematopoiesis, which leads to in life-threatening anemia, thrombocytopenia, greater susceptibility to infections, and secondary expansion of extramedullary hematopoiesis sites such as the liver and spleen.
Cutaneous extramedullary hematopoiesis has been encountered exceptionally in association with haematological malignancies.
In our patient, given the history of multiple myeloma, extramedullary hematopoiesis was also suggested.
Extramedullary hematopoiesis (hematopoiesis that occurs outside of the medulla of the bone) is associated with hematological disorders, such as thalassemias, myelofibrosis and other states of ineffective hematopoiesis, and is accompanied by chronic anemia, splenomegaly and marked hyperplasia on bone marrow aspirate.
Computed tomography (CT) guided biopsies the liver hypodensities showed normal bone marrow elements including maturing myeloid and erythroid components and megakaryocytes, consistent with extramedullary hematopoiesis.
Extramedullary hematopoiesis has been reported in patients with myeloproliferative disease.
An elevated skeletal density and abundant formation of the bones are the features that characterize osteopetrosis, which is a rare genetic disorder; it destroys the medullary cavity, resulting in extramedullary hematopoiesis, hepatosplenomegaly, anemia, and thrombocytopenia.
Firstly pregnancy can worsen preexisting anemia and also trigger red blood cell hemolysis which in turn induces massive extramedullary hematopoiesis giving rise to increase in splenic size and finally splenic rupture [2].