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myeloid metaplasia
Pathology:
1) occurs in association with myelofibrosis
2) bone marrow
a) panhypoplasia (85%)
b) fibroblast proliferation (may be primary event)
c) myelofibrosis
d) osteosclerosis
3) splenomegaly
- extramedullary hematopoiesis in sinusoids of red pulp
4) hepatomegaly
a) engorgement with blood
b) extramedullary hematopoiesis
c) hemosiderosis
5) anemia secondary to:
a) ineffective erythropoiesis
b) expanded plasma volume
c) blood loss
d) hemolysis
Clinical manifestations:
1) splenomegaly (100%)
2) hepatomegaly (70%)
Laboratory:
1) complete blood count (CBC) shows anemia
2) peripheral smear
a) leukoerythroblasts (96%)
b) dacrocytes (tear-drop cells)
3) bone marrow biopsy - myelofibrosis
4) serum vitamin B12 & serum folate
5) fecal occult blood
Complications:
1) esophageal varices
2) microinfarcts in the gut
Management:
1) also see myelofibrosis
12) 80% of asymptomatic patients will remain asymptomatic at 5 years if untreated
3) transfusion with packed RBC for symptomatic anemia
4) androgens for ineffective erythropoiesis
a) testosterone enanthate 400-600 mg/week
b) fluoxymesterone 10 mg TID
c) favorable response in 40% of males & 32% of females
5) corticosteroids for hemolysis
6) treat vitamin B12 deficiency & folate deficiency if indicated
7) allogeneic stell cell transplantation for patients < 55 years of age
8) pressure symptoms from splenomegaly
a) hydroxyurea
b) splenic irradiation
c) splenectomy is associated with hemorrhagic & thrombotic complications, increased risk of progression to AML & has no benefit for survival [2]
9) overall 5 year survival is 60%
Related
metaplasia
myelofibrosis
Specific
panmyelosis
General
myeloproliferative disorder
References
- Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed)
Lippincott-Raven, Philadelphia, 1998, pg 434-35
- Medical Knowledge Self Assessment Program (MKSAP) 11, 14,
American College of Physicians, Philadelphia 1998, 2006