Expression of LEF1 in m antle c ell l ymphoma

• Published in: Annals of diagnostic pathology 2016
• Main Authors: O ' Malley, Dennis P., M.D, Lee, John P., D.O, Bellizzi, Andrew M, M.D
• Format: Article
• Language: English
• Subjects: Pathology
• ISSN: 1092-9134
• DOI: 10.1016/j.anndiagpath.2016.09.016

Abstract Small lymphocytic lymphoma/chronic lymphocytic leukemia (CLL/SLL) and mantle cell lymphoma (MCL) usually are distinctly different in regard to clinical presentation, morphology, immunophenotype and molecular/genetic findings. In spite of this, select cases may show overlapping characteristics and represent a diagnostic challenge. Recently LEF1 staining was identified as a fairly characteristic finding in CLL/SLL, with positivity identified in up to 95% of cases. LEF1 staining has not been reported as being present in cases of MCL, making this stain a useful tool in distinguishing these diagnoses. We identified an index case of MCL with cyclin D1 expression and the presence of the typical t(11;14) IGH-CCND1 , which expressed LEF1. Subsequently, we assessed LEF1 immunohistochemical staining in a series of 23 cases of MCL, as confirmed by staining for cyclin D1 and/or SOX11. We found expression present in one additional case, and evaluated some published literature suggesting a frequency of 4 – 9% expression of LEF1 by MCL. LEF1 expression by immunohistochemistry in MCL is unusual but can be seen rarely, and could represent a potential diagnostic pitfall.