Comparison and Development of Immunohistochemical Diagnostic Criteria for Blastic Plasmacytoid Dendritic Cell Neoplasm

Kana Sakamoto; Satoko Baba; Yuka Okumura; Shuji Momose; Sawako Ono; Akiko Tonooka; Ryo Ichinohasama; Emi Takakuwa; Hideki Nakasone; Koichi Ohshima; Kengo Takeuchi

doi:10.1016/j.modpat.2023.100253

Comparison and Development of Immunohistochemical Diagnostic Criteria for Blastic Plasmacytoid Dendritic Cell Neoplasm

Mod Pathol. 2023 Oct;36(10):100253. doi: 10.1016/j.modpat.2023.100253. Epub 2023 Jun 26.

Authors

Kana Sakamoto¹, Satoko Baba¹, Yuka Okumura², Shuji Momose³, Sawako Ono⁴, Akiko Tonooka⁵, Ryo Ichinohasama⁶, Emi Takakuwa⁷, Hideki Nakasone⁸, Koichi Ohshima⁹, Kengo Takeuchi¹⁰

Affiliations

¹ Pathology Project for Molecular Targets, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan; Division of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
² Department of Pathology and Laboratory Medicine, Nagoya University Hospital, Nagoya, Japan.
³ Department of Pathology, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
⁴ Department of Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
⁵ Division of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan; Department of Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Komagome Hospital, Tokyo, Japan.
⁶ Division of Hematopathology, Tohoku University Hospital, Sendai, Japan.
⁷ Department of Surgical Pathology, Hokkaido University Hospital, Sapporo, Japan.
⁸ Division of Hematology, Saitama Medical Center, Jichi Medical University, Saitama, Japan.
⁹ Department of Pathology, Kurume University, School of Medicine, Kurume, Japan.
¹⁰ Pathology Project for Molecular Targets, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan; Division of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan; Clinical Pathology Center, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan. Electronic address: kentakeuchi-tky@umin.net.

PMID: 37380058
DOI: 10.1016/j.modpat.2023.100253

Abstract

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy derived from the precursors of plasmacytoid dendritic cells. Diagnostic criteria for BPDCN have not been fully established. BPDCN is often diagnosed without other BPDCN markers than the 3 conventional markers (CD4, CD56, and CD123) in practice and case reports, although acute myeloid leukemia/myeloid sarcoma (AML/MS), which is always considered in the differential diagnosis of BPDCN, can express them. We reviewed published case reports on BPDCN and found that the diagnosis was made without any other BPDCN markers than the conventional markers in two-thirds of the cases. Next, 4 representative existing diagnostic criteria were applied to 284 cases of our cohort of BPDCN and mimics. The results differed in 20% (56/284) of the cases. The criterion based on the 3 conventional markers alone had a low concordance rate (80%-82%) with the other 3 criteria, which were almost concordant with each other. However, newly found minor limitations in these criteria prompted us to devise new diagnostic criterion for BPDCN composed of TCF4, CD123, TCL1, and lysozyme. We also revealed that CD123-positive AML/MS patients had a significantly poorer outcome than those with BPDCN and that 12% (24/205) of the cases were non-BPDCN even if all 3 conventional markers were positive, thus clarifying the risk of diagnosing BPDCN without more specific markers. In addition, histopathological features, such as the reticular pattern, which is not seen in BPDCN and suggests AML/MS, were also identified.

Keywords: BPDCN; CD123; TCF4; immunohistochemistry; lysozyme; reticular pattern.