Agnogenic Myeloid Metaplasia with Myelofibrosis AMM MF

Definition

• Clonal myeloproliferauon with reactive marrow fibrosis & extramedullary hematopoiesis Etiologies of myelophthisis (marrow replacement)

• 1 ° agnogenic myeloid metaplasia with myelofibrosis; post-PV ET myeloid metaplasia

• 2° hematologic (eg. leukemia. MDS) or metastatic malignancies (eg. breast, prostate)

collagen vascular disorders (eg. SLE)

toxins (eg. benzene, radiation)

granulomas from infection (eg. TB. fungal) or sarcoid deposition diseases (eg. Gauchers disease)

Clinical manifestations (NEJM 2000.342 1 255)

• Ineffective erythropoiesis — anemia; extramedullary hematopoiesis — massive splenomegaly (abdominal pain, early satiety) • hepatomegaly

• Tumor bulk and * cell turnover fatigue, weight loss, fever, sweats

Diagnostic evaluation

• Anemia with variable WBC and platelet counts

• Peripheral smear - • "leukoerythroblastic" (teardrop cells, nucleated RBCs.

immature WBCs); large abnormal platelets

• BM aspirate - "dry" tap; BM bx . severe fibrosis, replacement by reticulin & collagen

• Need to r o CML (absence of Ph chromosome. BCR-ABL translocation)

Treatment

• Allogeneic HSCT only potential cure -» consider in young Pts with poor prognosis

• Supportive care: transfusions; inconsistent benefit from androgens or epo;

splenectomy for blood counts refractory to transfusion or painful splenomegaly

• Hydroxyurea for significant leukocytosis or thrombocytosis Complications and prognosis

• Median survival 5 y. transformation into AML occurs at a rate of 8% y

• Worse prognosis with Hb 10 g dl or with either WBC 30.000 nL or WBC 4.000 jxL

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