[1467] Algorithm for Paraffin-Based Subclassification of B-Cell Lymphoproliferative Disorders in Bone Marrow

Megan O Nakashima, Douglas W Warden, Sarah L Ondrejka, Jeffrey Lin, Lisa Durkin, Juraj Bodo, Eric D Hsi. Cleveland Clinic, Cleveland, OH

Background: We previously demonstrated the utility of pERK and LEF-1 immunohistochemical (IHC) stains in bone marrow biopsies (BMBs) for diagnosing hairy cell (HCL) and chronic lymphocytic leukemia (CLL) respectively. We used these with BCL-6, CD10 and Cyclin D1 IHC and MYD88 L265P mutation testing to determine diagnostic sensitivity (sens) and specificity (spec) of this non-flow-cytometry-based panel for subclassifying small B-cell lymphoproliferative disorders (LPD) in BMBs.
Design: Consecutive CLL, HCL, lymphoplasmacytic lymphoma (LPL), follicular lymphoma (FL), marginal zone lymphoma (MZL), mantle cell lymphoma (MCL), monoclonal B-cell lymphocytosis (MBL) and B-cell LPD not otherwise specified (B-NOS) cases with adequate tissue were selected with additional HCL cases (total n=71). We performed LEF-1, Cyclin D1, BCL-6, CD10 and pERK/CD20 IHC on decalcified formalin- or B5-fixed paraffin-embedded BMBs (staining thresholds pERK>70%, LEF-1>70%, Cyclin D1>20%, BCL-6>10%, CD10>50%). Allele-specific PCR for MYD88 L265P was performed on DNA extracted from formalin-FPE tissue when available (n=49).
Results: Results are summarized in table 1. LEF-1 was 100% sens and 100% spec for CLL. pERK was 100% sens for HCL and positive in one case of "atypical" CLL (aCLL; 98% spec). Cyclin D1 was 100% sens for MCL and 87% for HCL. BCL-6 sens and spec for FL was 57% and 97% respectively; CD10 was more sensitive for FL (sens 86%, spec 95%). BCL-6 was positive in one case of HCL variant (HCLv). MYD88 mutation analysis was 100% sens and 95% spec for LPL.

Table 1
 # positive (%)
Dx (n)pERKLEF-1Cyclin D1CD10BCL-6MYD88*
CLL (12)012 (100)0000
HCL (15)15 (100)013 (87)2 (13)00
FL (7)0006 (86)4 (57)0
MCL (9)009 (100)000
LPL (7)000005 (100)
MZL (13)00001 (8)1 (8)
MBL (3)0001 (33)00
aCLL (2)1 (50)00000
HCLv (2)00001 (50)0
B-NOS (1)000001 (100)
*Subset tested


Conclusions: Our IHC panel identified HCL, CLL, FL and MCL with high spec and sens and can be used on decalcified B5-fixed BMBs. By adding MYD88 mutational analysis, we can distinguish the great majority of small B-LPD in BMBs without flow cytometry. Cases negative for all analytes are highly enriched for (splenic) MZL. The rest are difficult to classify cases such as HCLv, MBL, B-NOS and aCLL. Based on these findings we propose an algorithm:


Category: Hematopathology

Monday, March 4, 2013 9:15 AM

Proffered Papers: Section C, Monday Morning

 

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