[1325] Blastic Plasmacytoid Dendritic Cell Neoplasm in Bone Marrow, a Clinicopathological Describtion of 14 Cases

Khaled M Alayed, Joseph D Khoury, Abdulaziz F Alshaikh, Tariq N Aladily, Sergej Konoplev, L Jeffrey Medeiros. University of Texas MD Anderson Cancer Center, Houston, TX; King Saud University, Riyadh, Saudi Arabia

Background: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare malignant neoplasm derived from precursors of plasmacytoid dendritic cells. Distinguishing BPDCN from acute myeloid leukemia (AML) is important because the therapeutic approaches are different. Distinguishing BPDCN from AML can be particularly problematic in patients who present with BM involvement, with or without cutaneous lesions. Unlike its cutaneous counterpart, the pathologic and clinical features of BPDCN involving the bone marrow (BM) remain poorly characterized.
Design: We searched our institutional archives for neoplasms diagnosed as BPDCN, CD4+/CD56+ hematodermic neoplasm, or blastic NK-cell lymphoma and selected cases with BM involvement. Clinical and diagnostic data were obtained by review of medical records.
Results: We identified 14 cases of BPDCN with bone marrow involvement. The patients included 10 men and 4 women with a median age of 64 years (range, 19-86 years). Eleven patients had BM involvement at presentation. Skin involvement was identified at presentation in 10 patients. Morphologically, the neoplastic cells in the BM had scant, agranular, occasionally vacuolated cytoplasm. The nucleus was frequently irregular, with fine chromatin and often had a prominent nucleolus. Patterns of BM involvement included: diffuse (6/11), interstitial (4/11) and focal (1/11). Eight-color flow cytometry immunophenotyping (FCI) showed that the blasts were positive for CD4 (12/13), CD56 (10/12), CD123 (8/8), and HLA-DR (8/8), as well as CD2 (3/9), CD7 (8/10) and CD33 (6/8). The blasts were negative for CD34 (10/10), surface CD3 (9/9), cytoplasmic CD3 (6/6), CD8 (7/7), CD13 (6/6), CD117 (6/6) and myeloperoxidase (8/8). IHC for TCL-1 was positive in all 8 cases tested. Conventional cytogenetic analysis showed random karyotypic abnormalities in 6 of 11 cases analyzed. TCR-γ gene rearrangements were positive in 3/5 cases, whereas TCR-β gene rearrangements were negative in all 5 cases. Follow up data were available for 13 patients. With a median follow-up of 12 months (range, 2 to 48 months), 8 patients had died of their disease, 4 were in remission and 1 recurred symptoms.
Conclusions: Bone marrow involvement is common in patients with BPDCN. These neoplasms can be distinguished from AML primarily by FCI immunophenotyping and TCL1 immunohistochemistry.
Category: Hematopathology

Tuesday, March 5, 2013 11:45 AM

Proffered Papers: Section C, Tuesday Morning

 

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