BPDCN: Difference between revisions
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On standard diagnostic panels the cases generally have the following features: | On standard diagnostic panels the cases generally have the following features: | ||
*BPCDN typically have features of primitive phenotype: the cells typically lie in the "blast area" - with dim to moderate CD45 expression with low side scatter. CD7 and TdT are frequently expressed. characteristically '''CD34 is absent''' | *BPCDN typically have features of primitive phenotype: the cells typically lie in the "blast area" - with dim to moderate CD45 expression with low side scatter. CD7 and TdT are frequently expressed. characteristically '''CD34 is absent''' | ||
*Lineage-defining markers of myeloid, T or B cell are not expressed: i.e. there is no expression of MPO, CD14 or lysozyme; cCD3 is not expressed, and CD19 is not expressed (as well as CD20, cCD22, CD79a) | *'''Lineage-defining markers of myeloid, T or B cell are not expressed''': i.e. there is no expression of MPO, CD14 or lysozyme; cCD3 is not expressed, and CD19 is not expressed (as well as CD20, cCD22, CD79a) | ||
*However myeloid lineage-associated features | *However '''one or more myeloid lineage-associated features may be detected''': expression of CD33 is relatively common (x%), CD117 may also be expressed (x%), CD13 may be found (x%). Therefore cases may fit the criteria to assign myeloid lineage | ||
It is therefore important that specific features of BPCDN are actively sought in cases where an AML diagnosis is based on expression of two myeloid-associated markers and where there is skin rash and absent CD34 expression. | It is therefore important that specific features of BPCDN are actively sought in cases where an AML diagnosis is based on expression of two myeloid-associated markers and where there is skin rash and absent CD34 expression. | ||
Revision as of 19:34, 29 December 2023
Blastic plasmacytoid dendritic cell neoplasm (BPDCN)
Morphologically the primitive cells may resemble monocytic AML, or may have less easy to define or even lymphoid morphology. TA skin rash is present in most cases. This is a rare diagnosis but one that presents some practical diagnostic difficulties since BPDCN is derived from myeloid cells and therefore shares morphological and some immunophenotypic characteristics which may overlap typical AML.
On standard diagnostic panels the cases generally have the following features:
- BPCDN typically have features of primitive phenotype: the cells typically lie in the "blast area" - with dim to moderate CD45 expression with low side scatter. CD7 and TdT are frequently expressed. characteristically CD34 is absent
- Lineage-defining markers of myeloid, T or B cell are not expressed: i.e. there is no expression of MPO, CD14 or lysozyme; cCD3 is not expressed, and CD19 is not expressed (as well as CD20, cCD22, CD79a)
- However one or more myeloid lineage-associated features may be detected: expression of CD33 is relatively common (x%), CD117 may also be expressed (x%), CD13 may be found (x%). Therefore cases may fit the criteria to assign myeloid lineage
It is therefore important that specific features of BPCDN are actively sought in cases where an AML diagnosis is based on expression of two myeloid-associated markers and where there is skin rash and absent CD34 expression.
Diagnostic criteria for BPDCN:
Bright expression of: CD56 is generally accompanied by CD36, CD38, CD43, CD71, and HLA-DR, To confirm the diagnosis look also for plasmacytoid dendritic cell (PDC) associated markers: .
Should express: bright CD56 and/or CD4
then
BPDCN associate markers:
CD123 expressed and one of: CD303, CD304, TCF4, TCL1
Or
CD123 not expressed but at least three of CD303, CD304, TCF4, TCL1 are expressed and context of negative markers (above) is met
NOTE also other hematologic malignancies may share similar phenotypes, therefore diagnosis requires correlation with morphology, histopathology, clinical information to make a definitive diagnosis