[1340] Clinicopathologic Features of Double Hit Lymphomas with BCL6 and MYC Gene Rearrangements.

Raju K Pillai, Malini Sathanoori, Steven H Swerdlow. University of Pittsburgh Medical Center, PA

Background: “Double hit” [DH] lymphomas with MYC and either BCL2 or BCL6 rearrangements (R) are considered very aggressive with many now included in the category B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL)(I-DLBCL/BL). However, data describing the DH cases is largely based on the MYC&BCL2 cases with only scattered MYC&BCL6-R cases reported.
Design: In order to assess the significance of MYC&BCL6-R DH cases, the clinical, morphologic, phenotypic and cytogenetic features of 6 cases from UPMC and 21 cases from the Mitelman database (DB) that had MYC&BCL6-R documented by classical and/or FISH cytogenetic (CG) studies, and lacked a BCL2-R, were reviewed (1/27 with MYC-R or partial deletion). A CG complexity categorization was performed if classical CG were available (NEJM, 354:2419). Kaplan-Meier curves were used for survival analyses.
Results: Most cases occurred in adults (Table 1). 5/6 UPMC cases were I-DLBCL/BL and 1 DLBCL. All were CD20+ and 5/6 had a germinal center (GC) phenotype by the Hans algorithm. 1/6 was BCL2+. Median Ki-67 score was 98% (35-100%). Patients received CHOP(2), BL therapy(1) or no specific therapy(2) plus 1 recent case. Diagnoses in the Mitelman DB cases included 5 DLBCL (24%), 4 BL (19%), 3 I-DLBCL/BL (14%), 2 B-ALL, 2 myeloma, 2 SMZL, 1 PEL, 1 FL and 1 CML-BC(myeloid). 11/11 were CD20+, 5/8 CD10+ and 2/2 BCL6+. MYC partners included IGH(8), BCL6(6) or other(7). BCL6 partners included IGH(3), IGL(6), MYC(4), IGH&MYC(1) or other(7). The median CG complexity score was 5 (0-21). 13/21 had simple and 8 complex CG abnormalities. The median survival was 180 days (Fig 1).

Clinical features of MYC&BCL6-R double hit cases

	UPMC	Mittelman
No. of patients	6	21
Age, median (range), yrs	83(51-89)	60(9-75)
Sex, M:F ratio	1:1	1:1
Site
-Lymph Node	0	3(30%)
-Bone marrow	1(17%)	3(30%)
-Other extranodal	5(83%)	4(40%)

Conclusions: MYC with BCL6 double hit lymphomas are often extranodal, frequently best classified as I-DLBCL/BL and usually have a GC phenotype. Overall survival for patients with MYC/BCL6-R is short, although occasional “low grade” cases are reported. Whether these patients would benefit from BL therapy is unclear.


Category: Hematopathology

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 181, Monday Morning