J-LSMS 2014 | Annual Archive

Journal of the Louisiana State Medical Society

Blastic Plasmacytoid Dendritic Cell Neoplasm: Report of a Case Presenting With Lung and Central Nervous System Involvement and Review of the Literature

Zhuang Feng, MD, PhD; Jun Zhou, MD; Gail Bentley, MD

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematopoietic malignancy with almost invariably cutaneous involvement and poor prognosis. We report a case of BPDCN in a 58-year-old man who presented with skin, lymph node, bone marrow, peripheral blood, lung, and central nervous system involvement. To the best of our knowledge, central nervous system (CNS) involvement as initial presenta- tion has not been reported since the latest World Health Organization (WHO) classification of tumors of the hematopoietic and lymphoid tissues in 2008. Review of the literature was performed on BPDCN cases published in 2008-2013 in PubMed. The major clinical, histopathologic, immunophenotypic, and cytogenetic aspects of the disease were discussed. Dermatologists and dermatopathologists should be aware of this rare disease for which nearly half of the patients present with only cutaneous lesions at diagnosis, as it may allow for early diagnosis and appropriate treatment.

INTRODUCTION Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematopoietic malignancy. The recognition and nomenclature of BPDCN has been dramatically evolving. BPDCN was first described by Adachi et al. in 1994 as a CD4+CD56+ cutaneous lymphoma. The World Health Or- ganization (WHO) classification of tumors of hematopoietic and lymphoid tissue in 2001 named it as blastic natural killer (NK)-cell lymphoma due to its CD56 expression. 1 Later, the European Organisation for Research and Treatment of Cancer (EORTC) classification of cutaneous lymphoma renamed it as CD4+CD56+ hematodermic neoplasm in 2005. 2 BPDCN was first suggested of dendritic cell origin by Lucio et al. in 1999. More recently, it was confirmed as a tumor of precursor plasmacytoid dendritic cells (PDCs) (Chaperot et al., 2001; Chaperot et al., 2004). PDCs produce type 1 interferon (IFN1) and play an important role in the modulation of innate and adaptive immunity. PDCs are produced in the bone marrow and account for less than 0.1% peripheral blood mononuclear cells. When immune response is activated, PDCs can be recruited into lymph nodes, tonsils, spleen, and mucosa-associated lymphoid tissue. 3 PDCs generally are not identified in skin and sub- cutaneous tissue, and how cutaneous involvement almost invariably occurs in BPDCN is unclear. In 2008, the latest

WHO classification renamed it as BPDCN as a distinct entity under the category of myeloid neoplasm. 4 The etiology of BPDCN is not, but it has been suggested to be associated with acute myeloid/myelomonocytic leukemia (Petrella et al., 2005; Herling et al., 2007). The literature of formerly called blastic NK-cell lym- phoma published prior to 2008 may be heterogeneous because CD56 can be expressed in other hematopoietic lineages, including true NK lymphoma and acute myeloid leukemia with monocytic differentiation. In addition, markers recently developed for PDCs, including CD123 (the interleukin-3 receptor), blood dendritic cell antigen 2 (BDCA2/CD303), 5 and T-cell leukemia/lymphoma 1 (TCL1) and CD2-associated protein (CD2AP), 6 were rarely tested in the literature published prior to 2008. In this article, we report a case of BDPCN presenting with skin, lymph node, bone marrow, peripheral blood, lung, and central nervous system involvement and have reviewed the literature since the latest WHO classification of tumors of hematopoietic and lymphoid tissue in 2008 to delineate the characteristics of the disease. METHODS Light microscopy slides were prepared from paraffin- embedded tissue sections and stained with routine hema-

2 J La State Med Soc VOL 166 January/February 2014

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