Abstract
Abstract 2684
NLPHL accounts for 6.5% of all Hodgkin lymphoma cases in the West. It is characterized by a nodular or a nodular & diffuse proliferation of scattered large atypical CD20+ neoplastic B-cells referred to as lymphocyte predominant (LP) cells and typically associated with small lymphocytes mainly of B-cell type. Patients with NLPHL typically have an indolent clinical course but can frequently relapse. Progression to a higher grade lymphoma, notably T-cell/Histiocyte rich B-cell lymphoma (T/HRBCL) has been described in a relatively small number of cases. Because of its rarity, limited information is available about the role of non-neoplastic lymphocytes in NLPHL. Some studies suggest that NLPHL with T-cell rich background may behave differently than the conventional type with predominance of B-cells within the nodules. The purpose of this study was to evaluate outcomes of differential tumor microenvironment namely B-cell versus T-cell rich in patients with NLPHL. We document the clinicopathologic profiles of 29 patients with biopsy proven NLPHL, consisting of 22 male & 7 female, median age 26 years (range, 13–80 years). All patients had lymphoadenopathy & 2 cases showed extranodal involvement in addition to nodal disease. Two patients had a bulky mass, and three had stage 4 disease at presentation. The pathological diagnoses was reviewed and confirmed by an expert hematopathologist in all 29 cases. The LP cells in all cases had a prototypic immunophenotype of CD20+, CD79a+, PU.1+, Bcl-6+, CD15− CD30− & Fascin−. T/HRBCL was excluded as all cases demonstrated preservation of follicular dendritic meshwork by CD21 staining. The meshwork was expanded in 20 cases & in 9 cases it was partially disrupted evincing an irregular architectural pattern. Epstein-Barr Virus encoded RNA by in situ hybridization was negative in 8/8 cases tested. 27/29 patients received systemic multi-agent chemotherapy consisting of: doxorubicin, bleomycin, vinblastine, and dacarbacin (ABVD), 24 patients; cyclophosphamide, doxorubicin, vincristin, and prednisone (CHOP), 2 patients; Rituximab + CHOP (R-CHOP), 1 patient. 9/29 (31%) cases underwent autologous stem cell transplant. One patient in stage 2A refused therapy and one patient (stage 3A) developed significantly decreased cardiac ejection fraction following initial 2 cycles of ABVD. Both of these cases did not have adequate follow-up information available.
Twelve of the 29 cases (42%) were designated as having T-cell rich background population, whereas 17 (58%) were considered as conventional variant with a vast predominance of non-neoplastic small lymphocytes being B-cells. A few of the cases seemed to show admixture of both B-cells & T-cells. Comparing T-cell rich & B-cell rich background NLPHL no significant differences were detected in clinical parameters: age, sex, and stage at presentation, absolute lymphocyte count, LDH & Hb. All 27 (100%) patients in this study responded to first-line treatment: 23 with complete response & 4 with partial response. 13/27 (48%) had relapse/s. Five cases had more than one relapses. No patient died within a clinical follow-up period ranging from 18 to 84 months. When the overall survival (OS) of T-cell rich NLPHL was compared with the conventional variant there was no statistical significance between the two groups (log rank p= 0.1206). However, comparison of relapse rate showed that cases with T-cell rich background had higher relapse rate as well as greater incidence of multiple relapses as compared to B-cell rich type of NLPHL even after adjusting for the type of treatment received (log rank p= 0.003). Moreover, 2/12 (17%) T-cell rich NLPHL cases showed transformation to a high grade lymphoma (both T/HRBCL) at the time of recurrence. These findings suggest that in NLPHL a tumor microenvironment rich in T-cells rather than B-cells is characterized by an unfavorable clinical course although OS appears to be similar. These cases perhaps represent a distinctive clinicopathologic variant within the framework of NLPHL. Lately, the term ‘NLPHL with nodules resembling T/HRBCL’ has been used to express the immunobiological overlap between these two entities. It is possible that such cases could be regarded as “intermediate lymphomas” treading between NLPHL and T/HRLBCL. Further studies using gene array profiling analysis may help clarify the molecular differences between these closely related entities.
No relevant conflicts of interest to declare.
Author notes
Asterisk with author names denotes non-ASH members.
