Semiquantitative evaluation of prominent morphologic features exerting a discriminating impact between ET and early-prefibrotic stage of PMF applied to generate histologic patterns in representative treatment-naive bone marrow biopsies
| Feature* . | ET, % . | PMF, % . |
|---|---|---|
| Increased cellularity (age-matched) | 10-20 | 80-100 |
| Neutrophil granulopoiesis | ||
| Increased quantity | ≤ 10 | 50-80 |
| Left-shifting | ≤ 10 | 20-50 |
| Erythropoiesis | ||
| Increased quantity | ≤ 10 | ≤ 10 |
| Left-shifting | ≤ 10 | 10-20 |
| Megakaryopoiesis | ||
| Increased quantity | 80-100 | 50-80 |
| Size | ||
| Small | 0 | 20-50 |
| Medium | 10-20 | 10-20 |
| Large | 20-50 | 20-50 |
| Giant | 20-50 | 10-20 |
| Histotopography | ||
| Endosteal translocation | 10-20 | 20-50 |
| Cluster formation: size | ||
| Small (≥ 3) | 10-20 | 50-80 |
| Large (> 7) | 0 | 20-50 |
| Cluster formation: quality | ||
| Dense | 0 | 20-50 |
| Loose | 20-50 | 50-80 |
| Nuclear features | ||
| Hypolobulation (bulbous/cloud-like) | ≤ 10 | 50-80 |
| Hyperlobulation (staghorn-like) | 50-80 | ≤ 10 |
| Maturation defects | 0 | 50-80 |
| Naked nuclei | 20-50 | 50-80 |
| Fibers | ||
| Increased reticulin (minor fibrosis, grade 1)18,19 | 0 | 20-50 |
| Increased collagen | 0 | 0 |
| Osteosclerosis | 0 | 0 |
| Feature* . | ET, % . | PMF, % . |
|---|---|---|
| Increased cellularity (age-matched) | 10-20 | 80-100 |
| Neutrophil granulopoiesis | ||
| Increased quantity | ≤ 10 | 50-80 |
| Left-shifting | ≤ 10 | 20-50 |
| Erythropoiesis | ||
| Increased quantity | ≤ 10 | ≤ 10 |
| Left-shifting | ≤ 10 | 10-20 |
| Megakaryopoiesis | ||
| Increased quantity | 80-100 | 50-80 |
| Size | ||
| Small | 0 | 20-50 |
| Medium | 10-20 | 10-20 |
| Large | 20-50 | 20-50 |
| Giant | 20-50 | 10-20 |
| Histotopography | ||
| Endosteal translocation | 10-20 | 20-50 |
| Cluster formation: size | ||
| Small (≥ 3) | 10-20 | 50-80 |
| Large (> 7) | 0 | 20-50 |
| Cluster formation: quality | ||
| Dense | 0 | 20-50 |
| Loose | 20-50 | 50-80 |
| Nuclear features | ||
| Hypolobulation (bulbous/cloud-like) | ≤ 10 | 50-80 |
| Hyperlobulation (staghorn-like) | 50-80 | ≤ 10 |
| Maturation defects | 0 | 50-80 |
| Naked nuclei | 20-50 | 50-80 |
| Fibers | ||
| Increased reticulin (minor fibrosis, grade 1)18,19 | 0 | 20-50 |
| Increased collagen | 0 | 0 |
| Osteosclerosis | 0 | 0 |
Semiquantitative evaluation (relative incidence, %): 0 indicates usually absent; ≤ 10, rare; 10-20, slight; 20-50, moderate; 50-80, manifest; and 80-100, overt.