Al-Nusair Jowan, Porter Nathaniel, Alagha Zakaria, Graffeo Vincent, Mahmud Waqas, Alshal Mohamed
Marshall University Joan C. Edwards School of Medicine, Huntington, WV, USA.
J Investig Med High Impact Case Rep. 2025 Jan-Dec;13:23247096251344723. doi: 10.1177/23247096251344723. Epub 2025 May 26.
Mature plasmacytoid dendritic cell proliferation (MPDCP) is a rare, clonal but nonmalignant entity often associated with myeloid neoplasms such as chronic myelomonocytic leukemia (CMML), myelodysplastic syndromes, and acute myeloid leukemia. While typically confined to the bone marrow, nodal MPDCP is exceedingly rare and may mimic blastic plasmacytoid dendritic cell neoplasm (BPDCN), posing diagnostic challenges. We report a 78-year-old male with CMML-1 and progressive cervical lymphadenopathy. Workup revealed monocytosis, ASXL1 and CBL mutations, and CMML. Lymph node biopsy showed paracortical expansion by small mononuclear cells with plasmacytoid features. Immunophenotyping identified a CD4+, CD123+, CD303+, HLA-DR+, lysozyme+, CD56- population, consistent with MPDCP. A subset expressed TdT and granzyme B, with a Ki-67 index of 20% to 30%. Next-generation sequencing confirmed the same ASXL1 and CBL mutations in the lymph node, supporting clonal relation to CMML. Key differential diagnoses included BPDCN, T-cell lymphomas, Langerhans cell histiocytosis, and Kikuchi-Fujimoto disease. Absence of CD56, mature cytomorphology, and molecular concordance favored MPDCP. This case highlights the importance of distinguishing nodal MPDCP from malignant mimics. MPDCP may reflect immune evasion, altered cytokine signaling, or clonal progression in myeloid neoplasms. The patient was initially treated with hydroxyurea, later transitioned to decitabine/cedazuridine (Inqovi) for disease progression. Follow-up marrow biopsy showed stable CMML-2 with persistent mutations, and the patient remains under close monitoring. Recognizing MPDCP in unusual locations is critical for accurate diagnosis and prognostication. Further studies are warranted to clarify its molecular pathogenesis and potential as a biomarker of disease evolution in CMML and related disorders.
成熟浆细胞样树突状细胞增殖（MPDCP）是一种罕见的、克隆性但非恶性的实体，常与慢性粒单核细胞白血病（CMML）、骨髓增生异常综合征和急性髓系白血病等髓系肿瘤相关。虽然MPDCP通常局限于骨髓，但淋巴结MPDCP极为罕见，可能会模仿母细胞性浆细胞样树突状细胞瘤（BPDCN），带来诊断挑战。我们报告了一名78岁男性，患有CMML-1且有进行性颈部淋巴结肿大。检查发现单核细胞增多、ASXL1和CBL突变以及CMML。淋巴结活检显示小单核细胞在副皮质区增生，具有浆细胞样特征。免疫表型分析确定了一个CD4+、CD123+、CD303+、HLA-DR+、溶菌酶+、CD56-的细胞群，符合MPDCP。一部分细胞表达末端脱氧核苷酸转移酶（TdT）和颗粒酶B，Ki-67指数为20%至30%。二代测序证实淋巴结中存在相同的ASXL1和CBL突变，支持与CMML的克隆关系。主要鉴别诊断包括BPDCN、T细胞淋巴瘤、朗格汉斯细胞组织细胞增生症和菊池-藤本病。CD56缺失、成熟的细胞形态和分子一致性支持MPDCP的诊断。该病例强调了区分淋巴结MPDCP与恶性模仿疾病的重要性。MPDCP可能反映了髓系肿瘤中的免疫逃逸、细胞因子信号改变或克隆进展。患者最初接受羟基脲治疗，后来因疾病进展改用地西他滨/西扎胞苷（Inqovi）。随访骨髓活检显示CMML-2稳定，突变持续存在，患者仍在密切监测中。在不寻常部位识别MPDCP对于准确诊断和预后评估至关重要。有必要进一步研究以阐明其分子发病机制以及作为CMML和相关疾病疾病演变生物标志物的潜力。
