Flow cytometry:MPAL
From haematologyetc.co.uk
Important Note
MPAL is uncommon (2-3% of acute leukaemia). Flow cytometry provides initial evidence of MPAL. However conclusions may subsequently be modified (e.g. by results of immunohistochemistry, cytogenetics, or genetics). It is important that the provisional nature of flow cytometry assignment of MPAL is acknowledged.
| Types and frequency MPAL mixed-phenotype forms | |
|---|---|
| MPAL with features of Myeloid and B-lineage (MPAL M/B) | This is the most common MPAL (more than 50% of MPAL cases). |
| MPAL with features of Myeloid and T-lineage (MPAL M/T) | The second most frequent form (over one third of MPAL cases). |
| MPAL with combinations: MPAL B/T (rare) or B/T/M (very rare) | These forms are infrequent (around 10% of MPAL cases) |
| MPAL with defining molecular features | Following further analysis cases may be assigned additionally as: MPAL with t(9;22) (q34.1;q11.2); BCR-ABL1; MPAL with t(v;11q23.3); with KMT2A re-arrangement |
| Requirements to assign lineage in mixed-phenotype forms of acute leukaemia |
|---|
1. The case should not meet the criteria to assign myeloid lineage
Click here to review criteria for myeloid lineage assignment
2. The case should not meet the criteria to assign B-lymphoid lineage
Click here to review criteria for B-lymphoid lineage assignment
3. The case should not meet the criteria to assign T-lymphoid lineage
Click here to review criteria for T-lymphoid lineage assignment
.
| To diagnose MPAL, the leukaemia should meet at least two of the tree criteria below | |
|---|---|
| 1. The case should not meet the criteria to assign myeloid lineage | |
| Click here to review criteria for myeloid lineage assignment | |
| Requirement 2 | |
| Ensure that other conditions that may resemble undifferentiated acute leukaemia are excluded: particularly consider whether marker patterns suggest any of the following: | |
| Requirement 3 | |
| Consider whether the case may be better described as Acute Leukaemia of Ambiguous Lineage - not otherwise specified (ALAL-NOS) - see guidance |