Acute Leukemia
AML not otherwise categorized
Blastic plasmacytoid dendritic cell neoplasm

Topic Completed: 1 August 2011

Revised: 20 November 2019

Copyright: (c) 2003-2019,, Inc.

PubMed search: blastic plasmacytoid dendritic cell neoplasm [title] skin

Dragos C. Luca, M.D.
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Cite this page: Luca D. Blastic plasmacytoid dendritic cell neoplasm . website. Accessed April 8th, 2020.
Definition / general
  • Clinically aggressive tumor derived from the precursors of plasmacytoid dendritic cells (also known as professional type 1 interferon producing cells or plasmacytoid monocytes), with a high frequency of cutaneous and bone marrow involvement and leukemic dissemination (WHO 2008)
  • Synonyms: blastic NK cell lymphoma, agranular CD4+ NK cell leukemia, blastic NK leukemia / lymphoma, agranular CD4+ CD56+ hematodermic neoplasm
  • Very rare (< 100 cases reported)
  • Usually ages 45+ years, but can affect all ages; mean age at diagnosis 61 – 67 years, also children
  • 75% male
  • Tumor cells may derive from plasmacytoid monocytes present in healthy volunteers, as both are CD4+ CD56+ CD43+ CD68+ HLA-DR+, negative for other markers (Am J Surg Pathol 2002;26:852)
  • Not associated with Epstein-Barr virus
  • May be associated with myelodysplasia
Clinical features
  • Skin (virtually 100%), bone marrow / peripheral blood (60 – 90%), lymph node (40 – 50%)
  • Solitary / multiple nodules/plaques; usually disseminated at presentation
  • Various cytopenias, especially thrombocytopenia
Case reports
Treatment and prognosis:
  • Aggressive, with poor response to chemotherapy; some respond initially but recur (Am J Clin Pathol 2002;117:41)
  • Median survival 12 – 14 months with 80 – 90% demonstrating initial response to chemotherapy
  • Relapse is the rule (skin, soft tissue, CNS); terminal fulminant leukemic phase in most cases
  • Rare long lasting remissions associated with young age, acute leukemia chemotherapy and allogeneic stem cell transplantation
  • 10 – 20% associated with or progress to AML or AMML, with or without underlying myelodysplasia (Cancer 2002;94:2401)
Postulated normal counterpart
  • Precursor of plasmacytoid dendritic cells (α-interferon producing cells)
Clinical images

Images hosted on other servers:

Infiltrated plaque on the leg

Gross description
  • Usually multiple bruise-like deep red plaques / tumors
Microscopic (histologic) description
  • Diffuse monotonous infiltrate of blasts (medium size with scant agranular cytoplasm, fine chromatin resembling AML blasts, irregular nuclei, small nucleoli) with NK cell lineage differentiation
  • Skin cases usually involve entire dermis (including adenexa) and may extend to subcutis but dont involve epidermis; Grenz zone present
  • Occasionally have single file pattern of infiltration; usually no coagulative necrosis, no angiocentric infiltrate, no angioinvasion
  • Lymph nodes: diffuse interfollicular and medullary involvement
  • Bone marrow: variable involvement from subtle to massive, with variable dysplasia
Microscopic (histologic) images

Contributed by Gabriel Lerner, MS4:

Case of the Week #474




Images hosted on other servers:

Skin biopsies

Various images

CD56+, CD43+, negative for CD45 and TdT

Fig 1: diffuse monotonous dermal infiltrate
of medium sized cells; 2: cells resemble
blasts with minimal cytoplasm and fine
immature chromatin; 3: CD56+; 4-TdT+

Cytology description
  • Membrane bound cytoplasmic microvacuoles (pearl necklace-like), pseudopod formation
Positive stains
Flow cytometry images

Images hosted on other servers:

Fig A - flow cytometry shows CD56+ and CD34 cells (upper
left), no surface CD3 (upper right), cytoplasmic CD3 and no
MPO (lower left), no CD13 or CD7 (lower right); B karyotype
shows unbalanced abnormalities of #11p, 15q and 18q

Molecular / cytogenetics description
  • No T or B cell receptor genes rearrangement; complex karyotypes, nothing specific
  • Six major recurrent abnormalities: 5q21 or 5q34 (72%), 12p13 (64%), 13q13 - 21 (64%), 6q23 - qter (50%), 15q (43%), -9 (28%, Blood 2002;99:4154)
Differential diagnosis
Board review style question #1
Which of the following immunophenotypic markers is typically negative in BPDCN?

A. CD56
B. CD123
C. CD3
D. CD4
Board review answer #1
C. CD3. All others are typically positive in BPDCN, but can also be positive in other neoplasms including acute myeloid leukemia.
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