| Myelophthisic anemia | |
|---|---|
| Specialty | Hematology  |
Myelophthisic anemia (ormyelophthisis) is a severe type ofanemia found in some people with diseases that affect thebone marrow. Myelophthisis refers to the displacement of hemopoietic bone-marrow tissue[1] byfibrosis,tumors, orgranulomas. The word comes from the rootsmyelo-, which refers to bone marrow, andphthisis, shrinkage or atrophy.
Myelophthisis can occur in the setting of chronicmyeloproliferative disease (e.g.myelofibrosis),leukemia,lymphoma, and metastaticcarcinoma ormyeloma. It is common in people who have chronic idiopathic myelofibrosis. It has been linked to small-cell lung cancer,breast cancer orprostate cancer thatmetastasizes to the bone marrow.[2]
Currently, the most common cause is displacement of bone marrow by metastatic cancer (extramedullary hematopoiesis tends to be modest). Other causes include myeloproliferative disorders (especially late-stage or spent polycythemia vera), granulomatous diseases, and (lipid) storage diseases. Myelofibrosis can occur in all of these.Factors that may contribute to decreased RBC production include a decreased quantity of functioning hematopoietic tissue, disordered metabolism related to the underlying disorder, and, in some cases, erythrophagocytosis.
Some cases of myelophthisis are thought to be related to the release ofcytokines that simulatefibroblastic proliferation andfibrosis in the marrow.[2]
The first test for diagnosis myelophthisis involves looking at a small sample of blood under a microscope. Myelophthisis is suggested by the presence ofred blood cells that containnuclei or are teardrop-shaped (dacryocytes), or immaturegranulocyte precursor cells which indicatesleukoerythroblastosis is occurring because the displaced hematopoietic cells begin to undergoextramedullary hematopoiesis. These immature granulocytes are seen in peripheral blood smears. Diagnosis is confirmed when a bone marrow biopsy demonstrates significant replacement of the normal bone marrow compartment byfibrosis, malignancy or other infiltrative process. The presence of immature blood cell precursors helps distinguish another cause ofpancytopenia,aplastic anemia, from myelophthisic anemia because inaplastic anemia the hematopoietic cells are damaged and immature blood cells are not seen in the peripheral blood.
There may be evidence ofextramedullary hematopoiesis[3] (marrow elements can be found in thespleen,liver).
Treatment of this disorder involves treatment of the underlying cancer.[2][4]