[1403] MNDA Is Expressed in a Subset of Marginal Zone Lymphomas and Is Useful in the Differential Diagnosis with Follicular Lymphoma

Aharon G Freud, Ahmad Monabati, Giovanna Roncador, Gabriela Gualco, Carlos Bacchi, Yasodha Natkunam. Stanford University, Stanford, CA; Spanish National Cancer Research Centre, Madrid, Spain; Consultoria em Patologia, Botucatu, Sao Paulo, Brazil

Background: The diagnosis of marginal zone lymphoma (MZL) is complicated by the lack of specific markers that distinguish it from other non-Hodgkin B cell lymphomas. Myeloid cell nuclear differentiation antigen (MNDA) is a nuclear protein that was recently shown to be expressed at high frequency in MZL. We evaluated MNDA expression in a series of extramedullary non-Hodgkin B cell lymphomas to assess the sensitivity and specificity of this antigen for the detection of MZL.
Design: Formalin-fixed paraffin embedded tissue sections from individual cases and tissue microarrays were stained for MNDA using a monoclonal antibody (clone 253, 1:50 dilution) on a Leica Bond-Max platform with EDTA antigen retrieval. Lymphoma diagnoses were confirmed by three hematopathologists using WHO 2008 criteria.
Results: A total of 405 B cell lymphomas were stained for MNDA. Approximately 69% of nodal MZL (NMZL), 56% of extranodal MZL (EMZL) and 20% of splenic MZL (SMZL) expressed MNDA. MNDA was infrequently expressed in mantle cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, high grade follicular lymphoma (FL), and diffuse large B cell lymphoma. No low grade FLs were positive for MNDA.

MNDA expression in non-Hodgkin B cell lymphomas

Diagnosis	Number MNDA positive	Percent MNDA positive
Follicular lymphoma, grade 1-2	0/64	0%
Follicular lymphoma, grade 3	3/41	7%
Diffuse large B cell lymphoma	2/61	3%
Nodal marginal zone lymphoma	11/16	69%
Extranodal marginal zone lymphoma	19/34	56%
Splenic marginal zone lymphoma	4/20	20%
Chronic lymphocytic leukemia/small lymphocytic lymphoma	4/30	13%
Mantle cell lymphoma	9/139	6%

Fifteen NMZLs and 30 EMZLs were also stained for CD43, a non-specific antigen expressed on subsets of NMZL and EMZL but rarely observed in FL and SMZL. Among these NMZLs and EMZLs, 2/15 and 10/30 were CD43(-)MNDA(-), 3/15 and 3/30 were CD43(+)MNDA(-), 3/15 and 10/30 were CD43(-)MNDA(+), and 7/15 and 7/30 were CD43(+)MNDA(+), respectively.
Conclusions: In our series, MNDA expression was positive in 49% of all MZLs but not in any low grade FLs. In addition, we found that subsets of NMZLs and EMZLs that were MNDA positive lacked detectable CD43 expression. Collectively, these data support the inclusion of MNDA in the diagnostic evaluation of B cell lymphomas, particularly those in which the differential diagnosis is between low grade FL and MZL.
Category: Hematopathology

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 213, Monday Morning