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Leukemia - Acute

AML not otherwise categorized

Acute panmyelosis with myelofibrosis

Reviewer: Daniela Mihova, M.D. (see Reviewers page)
Revised: 20 March 2013, last major update September 2012
Copyright: (c) 2001-2013, PathologyOutlines.com, Inc.


● Also called acute (malignant) myelofibrosis, acute (malignant) myelosclerosis, acute myelodysplasia with myelofibrosis
● Now a distinct entity in WHO (2008), but not previously (Ann Hematol 2004;83:513, Leuk Lymphoma 2004;45:681)
● Rare, rapid onset, aggressive, usually adults
● Weakness, fatigue, fever, bone pain, pancytopenia; usually no marked splenomegaly
● Median survival is 2-9 months

Case reports

● Successful treatment with biphosphonates (Eur J Haematol 2004;73:215)

Micro description

● Hypercellular marrow with erythroblasts, immature granulocytes, megakaryocytes
● Prominent megakaryocytic abnormalities with variation in size and dysplastic changes, immature granulocytes with dysplasia and immature erythrocytes
● Usually marked fibrosis (reticulin > collagen)
● Aspirate smear is often hypocellular due to marked fibrosis

Micro images

Bone marrow smear (Wright-Giemsa):
Numerous blasts, some CD61+,         Various images
also abnormal erythroid and granulocyte cells

Blasts and more mature granulocytes, also a large megakaryocyte with
a poorly lobulated nucleus and dispersed chromatin,
occasional neutrophils and late stage erythroblasts

Bone marrow biopsy:
Partial replacement of marrow by        Numerous blasts with some clustering
blasts and increased fibrous tissue

Lymph node biopsy:
Total effacement by blasts, also scattered     Blasts have fine chromatin and small but
megakaryocytes at various stages of     distinct nucleoli, mitotic figures are present

Site unspecified:

Acute panmyelosis with myelofibrosis

Increase in coarse reticulin fibers        Reticulin stain shows markedly hypercellular marrow
                        with proliferation of blasts and maturing cells,
                        and increase in coarse reticulin fibers

Positive stains

● CD34 and HLA-DR (Leuk Lymphoma 2004;45:1873)
Erythroblasts: glycophorin A, hemoglobin A
Granulocytes: myeloperoxidase, CD13, CD33 and CD117
Monocytes: lysozyme, CD68
Megakaryocytes: CD31, CD41, CD61, PAS and factor VIII

Negative stains

● Usually CD42b (Mod Pathol 2005;18:603), von Willebrand factor

Differential diagnosis

Acute megakaryoblastic leukemia: no prominent changes in granulocytes or erythroid cells
Chronic idiopathic myelofibrosis: marked splenomegaly and prominent dysplasia
● Metastatic carcinoma with desmoplasia
Myelodysplastic syndrome with myelofibrosis: lacks high percentage of blasts

End of Leukemia - Acute > AML not otherwise categorized > Acute panmyelosis with myelofibrosis

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