Open AccessEBV-Positive Primary Large B-Cell Lymphoma: The Role of Immunohistochemistry and XPO1 in the Diagnosis of Mediastinal Lymphomas
Author(s) -
Danielle L V Maracaja,
Vidya Puthenpura,
Salley Pels,
Dennis P. O’Malley,
Jeffrey Sklar,
Karin E. Finberg,
Mina L. Xu
Publication year - 2019
Publication title -
applied immunohistochemistry and molecular morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.868
H-Index - 60
eISSN - 1541-2016
pISSN - 1533-4058
DOI - 10.1097/pai.0000000000000820
Subject(s) - immunophenotyping , lymphoma , bcl6 , cd30 , pathology , cd20 , medicine , b cell , immunology , germinal center , antibody , antigen
Primary mediastinal (thymic) large B-cell lymphoma (PMBL) is described as almost always negative for Epstein-Barr virus (EBV). In the context of a mediastinal lymphoma, the distinction between PMBL, classical Hodgkin lymphoma, diffuse large B-cell lymphoma, and mediastinal gray-zone lymphoma can be very difficult; hence, EBV positivity often argues against PMBL. We present a 19-year-old man with mediastinal mass morphologically consistent with PMBL. The tumor expressed classic immunophenotype, including positivity for CD20, CD19, MAL, OCT2, BOB1, BCL6, CD79a, and subset positivity for CD30. However, the tumor was EBV-positive by in situ hybridization. Next-generation sequencing detected somatic mutations in XPO1 (E571K), SMARCB1 (L356fs), and MYCC (T73A). Although the immunophenotype and XPO1 mutation are characteristic of PMBL, EBV expression is uncommon. Since EBV positivity can occur in rare PMBLs, it should not be the deciding factor in the diagnosis. This is the first EBV-positive PMBL in which mutational profiling has been reported. Aside from providing diagnostic support, the finding of the XPO1 E571K mutation may suggest a targeted therapeutic option.