Morphologic, immunphenotypic and clinical discriminators between T-cell/histiocyterich large B-cell lymphoma and lymphocyte-predominant Hodgkin lymphoma

BACKGROUND Features of T-cell/histiocyte rich large B-cell lymphoma (THRLBCL) overlap with those of lymphocyte predominant Hodgkin lymphoma (LPHL). The two lymphomas may represent a spectrum of the same disease, and differentiation between the two can sometimes be difficult. We looked at histomorphologic, immunophenotypic and clinical information that may help differentiate the two entities. METHODS Cases of THRLBCL and LPHL were blindly reviewed and studied for histological pattern (nodular vs. diffuse), nuclear features and pattern of expression of CD20, CD30, CD57, epithelial membrane antigen (EMA) and Epstein-Barr virus (EBV). A score encompassing diffuse histology, high nuclear grade, CD20 single-cell pattern, CD30 +, CD57-, EMA-, and EBV + was estimated for the diagnosis of TCHRLBCL. RESULTS There were 58 cases, including 30 cases of TCHRLBL and 28 cases of LPHL. The median age was 36 years for TCHRLBCL and 21 years for LPHL ( P  = 0.0001). Three types of nuclei were identified (lymphocytic/histocytic, Reed-Sternberg and centroblast-like). The latter two high-grade nuclei were suggestive of TCHRLBCL. TCHRLBCL and LPHL, respectively, showed diffuse histology, 90% vs. 4% ( P  = 0.001), single CD20 + cells, 93% vs. 3.5% ( P  = 0.00004), CD30 + cells, 30% vs. 0% ( P  = 0.01), CD57 + cells, 41% vs. 93% ( P  = 0.008), EMA + cells, 27% vs. 60% ( P  = 0.113), EBV + cells, 24% vs. 0% ( P  = 0.117), high nuclear grade, 70% vs. 0% ( P  = 0.001), total score 2-7 (mean 4.68) vs. 0-2 (mean 0.72) ( P  = 0.001), high stage, 86% vs. 7% ( P  = 0.0001). CONCLUSION Our findings indicate that a combination of multiple parameters can help differentiate between the two diseases. Two cases originally diagnosed as LPHL were re-assigned the diagnosis of THRLBCL.