A patient's face with one side drifting into purple blood cells representing a hematologic neoplasmA patient's face with one side drifting into purple blood cells representing a hematologic neoplasm
CD123 is a key marker to
diagnose BPDCN*1-3
Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN)
Quick look at BPDCN
  • CD123 is an important marker that can support the identification of blood cancers4,5
  • The expression of CD123 can indicate BPDCN – a rare, clinically aggressive hematologic malignancy with poor outcomes*6-8
  • BPDCN is characterized by variable dermatologic and hematologic manifestations and can easily be mistaken for more common hematologic malignancies9-12
  • Cooperation with dermatologists and hemato-oncologists is key for a correct diagnosis of BPDCN8,13
  • Biopsies of skin, bone marrow or secondary sites are critical for accurate diagnosis of BPDCN2,11,14
  • The marker triad – CD123, CD4 and CD56 – helps confirm the diagnosis of BPDCN*1,3,6,10,11,15
* The diagnosis of BPDCN requires immunophenotyping and fundamentally relies on the demonstration of CD4, CD56, CD123, CD303, and TCL1 expression, together with a lack of expression of markers for B cells, T cells, myeloid or monocytic cells, and NK cells.1,2
Add the CD123 marker to your hematologic diagnostic panel when you suspect a hematologic malignancy1-3
Are you testing for CD123 in your hematologic panels?
CD123 is an important marker that can support the identification of blood cancers4,5
CD123 may be overexpressed in cancer cells and is associated with the development of diverse myeloid and lymphoid malignancies.4,5,16
Frequency of CD123 expression in malignant cells4
BPDCN 75–100% B-ALL 52–100% CML 53–88%
AML 55–97% CLL 4–10% NHL 2–33%
BPDCN 75–100% AML 55–97%
B-ALL 52–100% CLL 4–10%
CML 53–88% NHL 2–33%
What is BPDCN?
The expression of CD123 can indicate BPDCN – a rare, clinically aggressive hematologic malignancy with poor outcomes*6-8
  • BPDCN is an aggressive and deadly blood cancer with variable manifestations6
  • Mean time between onset of lesions and diagnosis of BPDCN was 6.2 months6
  • Median overall survival of 8 to 14 months after diagnosis9
  • BPDCN requires an early diagnosis to help improve patients’ poor outcomes and provide them with appropriate treatment1,8
Historical overall survival rate for patients diagnosed with BPDCN
CD123 is a key marker to diagnose BPDCN.*1-3
* The diagnosis of BPDCN requires immunophenotyping and fundamentally relies on the demonstration of CD4, CD56, CD123, CD303, and TCL1 expression, together with a lack of expression of markers for B cells, T cells, myeloid or monocytic cells, and NK cells.1,2
BPDCN derives from the precursors of plasmacytoid dendritic cells and has a high frequency of cutaneous and bone marrow involvement1,2,9,17
~85% to 90%
of patients present with skin lesions of variable dermatologic presentation9,10,11,17
  • Skin lesions vary in size, shape, and color, and are often nonpruritic in nature11
  • In the skin, BPDCN with low-density infiltrates may mimic an inflammatory condition2
  • Tumor cells predominantly infiltrate the dermis, sparing the epidermis2,11,17
~60% to 90%
of patients present with leukemic disease18
 
  • Primary sites of involvement include bone marrow and peripheral blood11,19
  • Secondary sites of involvement include lymph nodes and viscera1,11
Close cooperation with dermatologists and hemato-oncologists is key for a correct diagnosis of BPDCN.8,13
BPDCN’s similarity to other hematologic malignancies may contribute to misdiagnosis1
BPDCN may be confused with1,8,12,19-21
Acute myeloid leukemia (AML) Diffuse large B-cell lymphoma (DLBCL)
Chronic lymphocytic leukemia (CLL) Peripheral T-cell lymphoma (PTCL)
Adult T-cell leukemia/lymphoma (ATL/ATLL) Leukemia cutis
Chronic myelomonocytic leukemia (CMML) Cutaneous T-cell lymphoma (CTCL)
Diffuse large B-cell lymphoma (DLBCL)
Peripheral T-cell lymphoma (PTCL)
Leukemia cutis
Cutaneous T-cell lymphoma (CTCL)
How to diagnose BPDCN?
Biopsies of skin, bone marrow or secondary sites are critical for accurate diagnosis of BPDCN2,11,14
These are the main morphologic features of a BPDCN biopsy:
  • Diffuse, monomorphic infiltrate1
  • Medium-sized blast cells with irregular nuclei1,2
  • Fine chromatin2
  • At least 1 small nucleoli2
  • Malignant BPDCN cells do not typically infiltrate the epidermis2,11,17
Punch biopsy of a skin lesion
Punch biopsy of a skin lesion showing BPDCN
Punch biopsy of a skin lesion showing BPDCN (H & E stain, ×40). Inset shows medium-sized malignant cells sparing the epidermis (H & E stain, ×1000).13
Reprinted by permission of SAGE Publications, Inc.
Bone marrow core biopsy
Bone marrow core biopsy showing diffuse infiltration by BPDCN
Bone marrow core biopsy showing diffuse infiltration by BPDCN (H & E stain, ×600).13
Reprinted by permission of SAGE Publications, Inc.
Multidisciplinary cooperation reducing the lapse between lesion presentation and diagnosis may improve patient outcomes.8,13
The marker triad – CD123, CD4, and CD56 – helps confirm the diagnosis of BPDCN*1,3,6,10,11,15
  • In BPDCN, CD123 is a useful diagnostic marker and therapeutic target1,3,22
    – CD123 can be identified through any biopsy of malignant cells4
A graphic showing that BPDCN testing should include CD123, in combination with CD4 and CD56
* The diagnosis of BPDCN requires immunophenotyping and fundamentally relies on the demonstration of CD4, CD56, CD123, CD303, and TCL1 expression, together with a lack of expression of markers for B cells, T cells, myeloid or monocytic cells, and NK cells.1,2
  • Diagnosis of BPDCN requires multiple positive and negative markers23
Antigens that confirm the diagnosis
of BPDCN23-27		 Antigens that exclude the diagnosis
of BPDCN6,10,23-26,28		 Other markers that may be positive in BPDCN23,24*
  • CD123+
  • CD4+
  • CD56+
  • TCL1+
  • CD303 (BDCA2)+
  • TCF4+
  • CD3–
  • CD19–
  • TIA1–
  • Granzyme B–
  • Myeloperoxidase–Myeloper-
    oxidase–
  • Pan T-cell marker
    – CD3
  • Pan B-cell markers
    – CD79a, CD20
  • Markers of immaturity
  • Myeloid markers
    – CD11c
    – CD 163
    – Lysozyme
    – Myeloperoxidase
  • CD43
  • TdT
  • CD68
  • CD33
Antigens that exclude the diagnosis of BPDCN6,10,23-26,28
  • Pan T-cell marker
    – CD3
  • Pan B-cell markers
    – CD79a, CD20
  • Markers of immaturity
  • Myeloid markers
    – CD11c
    – CD 163
    – Lysozyme
    – Myeloper-
    oxidase
Other markers that may be positive in BPDCN23,24*
  • CD43
  • TdT
  • CD68
  • CD33
*One or more of these markers may be negative in some cases of BPDCN. Negativity does not rule out the diagnosis but does make it less likely.
Early and accurate diagnosis is critical to reach complete remission.9
Add CD123 marker to your hematologic diagnostic panel when you suspect hematologic malignancy1-3
Abbreviations
AML = acute myeloid leukemia;
ATL/ATLL = adult T-cell leukemia/lymphoma;
BPDCN = blastic plasmacytoid dendritic cell neoplasm;
CD = cluster of differentiation;
CMML = chronic myelomonocytic leukemia;
CLL = chronic lymphocytic leukemia;
CTCL = cutaneous T-cell lymphoma;
DLBCL = diffuse large B-cell lymphoma;
MDS = myelodysplastic syndrome;
NK = natural killer;
pDC = plasmacytoid dendritic cell;
PTCL = peripheral T-cell lymphoma;
TCL1 = T-cell leukemia/lymphoma protein 1A.
References
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  22. 21. Parsi M et al. LeukemiaCutis. [Updated 2021 Jul 21]. In: StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK541136/
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  27. 26. Garnache-Ottou F, et al. Br J Haematol. 2009;145(5):624-636.
  28. 27. Ceribelli M, et al. Cancer Cell. 2016;30(5):764-778.
  29. 28. Pennisi M, et al. Case Reports in Hematology. Published March 20, 2017. Accessed October 3, 2018.