• B-cell lymphoma (unclassifiable);
  • classical Hodgkin’s lymphoma;
  • immunohistochemistry;
  • mediastinal grey zone lymphoma;
  • primary mediastinal (thymic) large B-cell lymphoma;
  • tissue microarray

Hoeller S, Zihler D, Zlobec I, Obermann EC, Pileri SA, Dirnhofer S & Tzankov A (2010) Histopathology56, 217–228

BOB.1, CD79a and cyclin E are the most appropriate markers to discriminate classical Hodgkin’s lymphoma from primary mediastinal large B-cell lymphoma

Aims:  To clarify which immunohistochemical markers could be helpful in distinguishing between classical Hodgkin’s lymphoma (cHL) and primary mediastinal B-cell lymphoma (PMBCL) to more narrowly define ‘B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and cHL’.

Methods and results:  Two hundred and 83 cHLs and 51 PMBCLs were analysed on validated tissue microarray platforms with antibodies to BOB.1, CD15, CD20, CD23, CD30, CD79a, cyclin E, LMP-1, MUM1p, p63 and Oct2. The marker cut-off scores were calculated using receiver–operating characteristic curves. Markers with the highest positive predictive value for cHL were: CD15, cyclin E, LMP-1 (all 100%), MUM1p (93%) and CD30 (83%). High sensitivity was achieved only by CD30 (92%) and cyclin E (79%). Nineteen percent of PMBCLs were also positive for CD30, which led to a lower specificity of CD30 as regards cHL (81%) compared with cyclin E (100%). The antibodies with the highest positive predictive value for PMBCL were: CD23 (98%), p63 (96%), BOB.1 (94%) and CD79a (90%), with high sensitivity for BOB.1 (100%), CD79a (89%) and p63 (82%).

Conclusions:  The use of at least three of the most accurate immunohistochemical markers, cyclin E, CD79a and BOB.1, may be helpful in the differential diagnosis of cHL and PMBCL.