Clinicopathological analysis of 46 cases with CD4+ and/or CD56+ immature hematolymphoid malignancy: reappraisal of blastic plasmacytoid dendritic cell and -related neoplasms

Abstract

Aims

Here we aimed to investigate the clinicopathological features of CD4+ and/or CD56+ immature hematolymphoid malignancy (iHLM), including blastic plasmacytoid dendritic cell neoplasm (BPDCN).

Methods and results

We analysed the clinicopathological features of 46 patients consecutively diagnosed with CD4+/CD56+ iHLM. These cases were categorized into three groups based on their immunohistochemical expression of three plasmacytoid dendritic cell (pDC) markers (CD123, CD303, and TCL1): cutaneous BPDCN (n = 35), non-cutaneous BPDCN (n = 6), and non-BPDCN-type CD56+ neoplasms (n = 5). Compared to non-cutaneous BPDCN, cutaneous BPDCN was associated with an older median age at onset (72 vs. 45 years, P < 0.05), and higher positivity for CD4 (P < 0.05), CD123 (P < 0.05), and 2−3 pDC markers (89 vs. 50%, P = 0.05). Cutaneous BPDCN was divided into TdT+ and TdT− subgroups, which did not differ in prognosis, although TdT+ cases showed a lower median onset age (66 vs. 79 years, P < 0.05) and higher frequency of extracutaneous lesions (P < 0.05). Compared to the BPDCN groups, non-BPDCN-type CD56+ neoplasms cases showed higher cytoplasmic CD3 positivity (P < 0.05) and less frequent BCL-2 expression (P < 0.05), and lacked cutaneous lesions. However, the survival curves overlapped. Notably, one case involved an unusual composite neoplasm, comprising CD56+ lymphoblastic lymphoma and mature CD56+ cytotoxic T-cell lymphoma.

Conclusions

Our present data support the recognition of cutaneous BPDCN as a homogenous entity, in contrast to the non-cutaneous form. Additional research is warranted to characterize non-BPDCN-type CD56+ neoplasms.

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