A Clinical and Pathological Comparison of Different Immunomorphological Subvariants of Nodular Lymphocyte-Predominant Hodgkin’s Lymphoma at Initial Diagnosis

Background. Nodular lymphocyte-predominant Hodgkin’s lymphoma (NLPHL) is a rare Hodgkin’s lymphoma subtype with a variable growth pattern and immune tissue architecture of tumor. Clustering of patients into subgroups based on immunohistochemical (IHC) tumor subvariants is essential for prognosis assessment and development of new differentiated treatment approaches. Aim. To study clinical course of NLPHL in patients with different IHC-subvariants of the disease and identify a poor prognosis subgroup. Materials & Methods. From 2010 to 2017 the Department of Anatomic Pathology at the National Medical Hematology Research Center undertook morphological and IHC-analysis of lymph node and bone marrow core biopsies of 60 NLPHL patients: 47 men and 13 women (male/female ratio of 3.6:1) aged 17–68 years (median 37 years). IHC-analysis with expanded panel of antibodies was performed in all cases of determining IHC-subvariants in accordance with WHO-2017 classification. Results. The clinical and immunomorphological comparative study of NLPHL with variant immune tissue architecture allowed to divide the patient population into three subgroups with differently manifested areas similar to T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) in lymph node sections or other site biopsies. These subgroups are characterized by different clinical course of the disease. The subgroup with ≥ 50 % THRLBCL-like areas was marked by the prevalence of clinical stage IV and significantly larger amount of extranodal lesions. Conclusion. In NLPHL the most unfavorable clinical course is typical of the patients whose biopsies contain ≥ 50 % THRLBCL-like areas. Semi-quantification of THRLBCL-like areas allowed to define a spectrum of NLPHL IHC-subvariants correlating with the clinical course of the disease. The true transformation into diffuse large B-cell lymphoma is a rare event, it occurred in 2 (3 %) out of 60 patients.