Table 5

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and T cell/histiocyte-rich large B cell lymphoma

S/no.Diagnostic points and pitfalls
1.The presence of a prominent PD-1-positive T cell infiltrate and expanded FDC meshworks in NLPHL may raise the possibility of AITL. However, their pattern of FDC meshworks is distinct and AITL shows a polymorphic background cellular population.
2.In NLPHL, where the LP cells are usually CD30 and EBV negative, there may be non-neoplastic activated cells/immunoblasts that may be strongly positive for CD30 and occasionally positive for EBV on EBER-ISH. If attention is not paid to the type of cells expressing CD30 and EBER (ie, neoplastic vs bystander cells), the pathologist may misdiagnose NLPHL as CHL.
3.Patients with recurrent NLPHL may have previously received anti-CD20 therapy that may lead to loss of CD20 expression in the LP cells. This should not be considered as inherent CD20 absence favouring CHL.
4.Oct-2 is a highly sensitive immunohistochemical marker for the LP cells in NLPHL and can be helpful as a reference marker in localising the LP cells for comparison with other immunohistochemistry stains.
5.NLPHL can have a diffuse T cell-rich pattern, which may predominate. This diffuse pattern is especially common in recurrences and bone marrow involvement. In a small biopsy or bone marrow sample, this can be indistinguishable from TCHRLBCL as the large cells are morphologically and immunohistochemically similar. The pathologist should be cautious in making a diagnosis of de novo TCHRLBCL in such specimens, especially when there is no antecedent history of TCHRLBCL and/or the clinical picture is atypical for TCHRLBCL (eg, localised disease).
6.In NLPHL with a predominant diffuse T cell-rich pattern, generous sampling and immunohistochemistry across multiple sections to identify FDC meshworks and B cell-rich nodules may be required as these may be very focal.
7.In a biopsy morphologically consistent with TCHRLBCL, correlation with clinical history is important. If a history of NLPHL is present, classification as ‘TCHRLBCL-like transformation’ of NLPHL rather than de novo TCHRLBCL is appropriate.
  • AITL, angioimmunoblastic T cell lymphoma; CHL, classical Hodgkin lymphoma; EBER-ISH, Epstein-Barr virus by in situ hybridisation for EBER; EBV, Epstein-Barr virus; FDC, follicular dendritic cell; LP, lymphocyte-predominant; TCHRLBCL, T cell/histiocyte-rich large B cell lymphoma.