MPAL: Difference between revisions
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!colspan="2" <span style="font-size:90%; font-color:navy; style="text-align: left; border: 1px solid black; background:pale gray">|''' | !colspan="2" <span style="font-size:90%; font-color:navy; style="text-align: left; border: 1px solid black; background:pale gray">|'''What features must be met to diagnose acute undifferentiated leukaemia'''</br></span> | ||
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|colspan="2" style = "font-size:90%; color:black; background:#ddeee1" |''' | |colspan="2" style = "font-size:90%; color:black; background:#ddeee1" |'''Requirement 1''' | ||
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|colspan="2" style = "font-size:90%; color:black;"|'''Required''' No lineage assignment can be made for myeloid, B-lymphoid or T-lymphoid using the criteria above | |colspan="2" style = "font-size:90%; color:black;"|'''Required''' No lineage assignment can be made for myeloid, B-lymphoid or T-lymphoid using the criteria above | ||
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|colspan="2" style = "font-size:90%; color:black; background:#ddeee1" |''' | |colspan="2" style = "font-size:90%; color:black; background:#ddeee1" |'''Requirement 2''' | ||
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|colspan="2" style = "font-size:90%; color:black;"|No more than one lineage-associated (but not lineage-defining marker) for any lineage should be expressed | |colspan="2" style = "font-size:90%; color:black;"|No more than one lineage-associated (but not lineage-defining marker) for any lineage should be expressed | ||
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|colspan="2" style = "font-size:90%; color:black; background:#ddeee1" |''' | |colspan="2" style = "font-size:90%; color:black; background:#ddeee1" |'''Requirement 3''' | ||
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|colspan="2" style = "font-size:90%; color:black;"|Markers mainly associated with the primitive nature of leukaemic cells do not allow lineage assignment (e.g. CD34, TdT, CD7, CD56, CS38) and are frequently seen in undifferentiated acute leukaemia | |colspan="2" style = "font-size:90%; color:black;"|Markers mainly associated with the primitive nature of leukaemic cells do not allow lineage assignment (e.g. CD34, TdT, CD7, CD56, CS38) and are frequently seen in undifferentiated acute leukaemia | ||
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|colspan="2" style = "font-size:90%; color:black; background:#ddeee1" |'''Requirement 4''' | |||
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|colspan="2" style = "font-size:90%; color:black;"|It is essential that other conditions that may resemble undifferentiated acute leukaemia are excluded: these may particu;arly include: non haematopoietic tumours, blastic plasma cell dendritic neoplasm, and rarely plasma cell leukaemias (often this requires that the wider context of the clinical history and marker pattern are considered. | |colspan="2" style = "font-size:90%; color:black;"|It is essential that other conditions that may resemble undifferentiated acute leukaemia are excluded: these may particu;arly include: non haematopoietic tumours, blastic plasma cell dendritic neoplasm, and rarely plasma cell leukaemias (often this requires that the wider context of the clinical history and marker pattern are considered. |
Revision as of 15:40, 27 July 2023
Final lineage in MPAL requires integration of additional molecular features, so assigments made by flow should be regarded as "provisional" pending full molecular assessment.
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Requirements to assign myeloid lineage in MPAL
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Marker option 1 | |
Myeloperoxidase (MPO) | This marker alone is sufficient to establish myeloid lineage provided it meets the intensity definition - intensity should be at least half of that of mature neutrophils in at least of proportion of cells. |
marker option 2 | |
If MPO does not meet criteria for myeloid lineage, then myeloid lineage may still be assigned through demonstration of monocytic lineage. This can be assigned by the detection of at least two of the following features: By flow cytometry: CD11c, CD14, CD64; by other approaches: raised lysozyme in serum or urine or non-specific esterase in malignant cells (enzyme cytochemistry) |
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Requirements to assign B-lymphoid lineage in MPAL
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Marker option 1 | |
Required Strong expression of CD19 | To meet the definition of "strong" the expression intensity must exceed that of 50% of normal B lymphocytes |
In addition: CD10, CD22, or CD79a | If CD19 is strong then B-lineage can be assigned if there is at least ONE of these additional markers |
Marker option 2 | |
Required Weak expression of CD19 | To meet the definition of "weak" the expression intensity must be less than that of 50% of normal B lymphocytes |
In addition: CD10, CD22, or CD79a | If CD19 is strong then B-lineage can be assigned if there is at least TWO of these additional markers |
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Requirements to assign T-lymphoid lineage in MPAL
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Marker requirement | |
Either CD3 surface or cytoplasm (strong) | To meet the definition of "strong" the expression intensity must exceed that of 50% of normal T lymphocytes |
Or CD3 by immunocytochemistry (strong) | For immunohistochemistry it is important a non-zeta chain reagent is used |
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What features must be met to diagnose acute undifferentiated leukaemia
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---|---|
Requirement 1 | |
Required No lineage assignment can be made for myeloid, B-lymphoid or T-lymphoid using the criteria above | |
Requirement 2 | |
No more than one lineage-associated (but not lineage-defining marker) for any lineage should be expressed | |
Requirement 3 | |
Markers mainly associated with the primitive nature of leukaemic cells do not allow lineage assignment (e.g. CD34, TdT, CD7, CD56, CS38) and are frequently seen in undifferentiated acute leukaemia | |
Requirement 4 | |
It is essential that other conditions that may resemble undifferentiated acute leukaemia are excluded: these may particu;arly include: non haematopoietic tumours, blastic plasma cell dendritic neoplasm, and rarely plasma cell leukaemias (often this requires that the wider context of the clinical history and marker pattern are considered. |