Criteria for the diagnosis of myelofibrosis
| Primary myelofibrosis . | Myelofibrotic transformation of ET or PV . |
|---|---|
| Requires A1 + A2 and any 2 B criteria | Requires A1 + A2 and any 2 B criteria |
| A1: Bone marrow fibrosis ≥ 3 (on 0-4 scale) | A1: Bone marrow fibrosis ≥ 3 (on 0-4 scale) |
| A2: Pathogenetic mutation (eg, in JAK2 or MPL) or absence of both BCR-ABL1 and reactive causes of bone marrow fibrosis | A2: Previous diagnosis of ET or PV |
| B1: Palpable splenomegaly | B1: New palpable splenomegaly or increase in spleen size of ≥ 5 cm |
| B2: Unexplained anemia | B2: Unexplained anemia with 2 g/dL decrease from baseline hemoglobin |
| B3: Leukoerythroblastic blood film | B3: Leukoerythroblastic blood film |
| B4: Teardrop-shaped red cells | B4: Teardrop-shaped red cells |
| B5: Constitutional symptoms* | B5: Constitutional symptoms* |
| B6: Histological evidence of extramedullary hematopoiesis | B6: Histological evidence of extramedullary hematopoiesis |
| Primary myelofibrosis . | Myelofibrotic transformation of ET or PV . |
|---|---|
| Requires A1 + A2 and any 2 B criteria | Requires A1 + A2 and any 2 B criteria |
| A1: Bone marrow fibrosis ≥ 3 (on 0-4 scale) | A1: Bone marrow fibrosis ≥ 3 (on 0-4 scale) |
| A2: Pathogenetic mutation (eg, in JAK2 or MPL) or absence of both BCR-ABL1 and reactive causes of bone marrow fibrosis | A2: Previous diagnosis of ET or PV |
| B1: Palpable splenomegaly | B1: New palpable splenomegaly or increase in spleen size of ≥ 5 cm |
| B2: Unexplained anemia | B2: Unexplained anemia with 2 g/dL decrease from baseline hemoglobin |
| B3: Leukoerythroblastic blood film | B3: Leukoerythroblastic blood film |
| B4: Teardrop-shaped red cells | B4: Teardrop-shaped red cells |
| B5: Constitutional symptoms* | B5: Constitutional symptoms* |
| B6: Histological evidence of extramedullary hematopoiesis | B6: Histological evidence of extramedullary hematopoiesis |
Criteria adapted from Campbell and Green.1
ET indicates essential thrombocythemia; and PV, polycythemia vera.
Drenching night sweats, weight loss >10% over 6 months, unexplained fever (>37.5°C) or diffuse bone pains.