Flow Cytometry Analysis of Recurrent or Persistent Lymphadenopathy in Patients with Nodular Lymphocyte-Predominant Hodgkin Lymphoma

Objectives: We recently examined the utility of flow cytometric analysis in the diagnosis of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) by examining reactive T-cell features. This study aims to compare these features in sequential biopsies of persistent or recurrent lymphadenopathy in patients with NLPHL. Methods: We reanalysed the histopathology and flow cytometry findings of 9 patients with multiple biopsies for persistent or recurrent lymphadenopathy and either initial or recurrent NLPHL. A flow cytometry signature was considered suggestive of NLPHL if ≥12% of T-cells expressed CD57 or ≥3% of T-cells co-expressed CD4 and CD8. Results: A flow cytometry signature considered suggestive of NLPHL was seen in 18 of 20 specimens. Based on histopathology, 11 were diagnosed as NLPHL, 3 were initially underdiagnosed as atypical lymphoid proliferation, and 4 were initially incorrectly diagnosed as negative or progressive transformation of germinal centers. Flow cytometry showed similar expression patterns of CD57 and CD4/CD8 in T-cells between initial and subsequent biopsies. The remaining 2 specimens lacked the flow cytometry signature suggestive of NLPHL and were histopathologically diagnosed as reactive hyperplasia. Conclusion: Flow cytometry analysis based on our criteria is highly sensitive in detecting NLPHL. Correlation with the cytospin cytology may increase the diagnostic specificity. A negative flow essentially ruled out the possibility of NHLPHL.