Case Report: Chronic myelomonocytic leukemia with mature plasmacytoid dendritic cell proliferation initially classified as MDS-IB2
- 1Department of Medical Laboratory, Dazhou Integrated Traditional Chinese Medicine and Western Medicine Hospital, Dazhou Second People’s Hospital
Abstract
Background: Mature plasmacytoid dendritic cell proliferation (MPDCP) is uncommon in myeloid neoplasms and can complicate diagnosis when dysplasia, increased blasts, monocytosis and pDC expansion coexist.
Case presentation: An 88-year-old man presented with anemia, thrombocytopenia, and marked monocytosis. Peripheral blood and bone marrow findings showed atypical monocytes, multilineage dysplasia, 13.5% myeloblasts, and an expanded pDC-like population. Flow cytometry identified a pDC-like population accounting for 8.60%, with CD4, bright CD123, CD303 and partial CD304 expression, and absence of CD34, CD117 and CD56. Cytogenetic and molecular testing revealed a complex karyotype with monosomy 7 and a TP53 mutation. The patient was initially diagnosed with MDS with increased blasts-2 (MDS-IB2) with MPDCP. Retrospective review of longitudinal blood counts demonstrated persistent monocytosis that predated the initial hematologic evaluation and persisted during follow-up. Together with the marrow morphology and clonal genetic abnormalities, these findings supported reclassification as CMML-2 with MPDCP.
Conclusion: This case highlights the value of longitudinal monocytosis in recognizing CMML when dysplasia, increased blasts, and MPDCP complicate the initial diagnosis, and underscores the importance of distinguishing the pDC population from myeloid blasts during disease classification.
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BibTeX
@article{chen2026case,
title = {{Case Report: Chronic myelomonocytic leukemia with mature plasmacytoid dendritic cell proliferation initially classified as MDS-IB2}},
author = {Junhong Chen and Juan Liu and Yanying Ren},
journal = {Frontiers in Oncology},
year = {2026},
month = oct,
doi = {10.3389/fonc.2026.1961676},
url = {https://www.frontiersin.org/articles/10.3389/fonc.2026.1961676/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Case Report: Chronic myelomonocytic leukemia with mature plasmacytoid dendritic cell proliferation initially classified as MDS-IB2
AU - Junhong Chen
AU - Juan Liu
AU - Yanying Ren
PY - 2026
DA - 2026/10/22
JO - Frontiers in Oncology
DO - 10.3389/fonc.2026.1961676
UR - https://www.frontiersin.org/articles/10.3389/fonc.2026.1961676/full
AB - Background: Mature plasmacytoid dendritic cell proliferation (MPDCP) is uncommon in myeloid neoplasms and can complicate diagnosis when dysplasia, increased blasts, monocytosis and pDC expansion coexist. Case presentation: An 88-year-old man presented with anemia, thrombocytopenia, and marked monocytosis. Peripheral blood and bone marrow findings showed atypical monocytes, multilineage dysplasia, 13.5% myeloblasts, and an expanded pDC-like population. Flow cytometry identified a pDC-like population accounting for 8.60%, with CD4, bright CD123, CD303 and partial CD304 expression, and absence of CD34, CD117 and CD56. Cytogenetic and molecular testing revealed a complex karyotype with monosomy 7 and a TP53 mutation. The patient was initially diagnosed with MDS with increased blasts-2 (MDS-IB2) with MPDCP. Retrospective review of longitudinal blood counts demonstrated persistent monocytosis that predated the initial hematologic evaluation and persisted during follow-up. Together with the marrow morphology and clonal genetic abnormalities, these findings supported reclassification as CMML-2 with MPDCP. Conclusion: This case highlights the value of longitudinal monocytosis in recognizing CMML when dysplasia, increased blasts, and MPDCP complicate the initial diagnosis, and underscores the importance of distinguishing the pDC population from myeloid blasts during disease classification.
SN - 2234-943X
ER -