The Clinicopathological Features Of Rare B-cell Lymphoma In Children Or Young People

Background and objectLymphoma is a highly heterogeneous disease and one of the most common malignancies,most of which are non-Hodgkin's lymphoma.The common types of non-hodgkin's lymphoma in adults are diffuse large B cell lymphoma,extranodal NK/T-cell lymphoma,extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue and follicular lymphoma.Non-Hodgkin's lymphomas in children and adults differ widely in biology,morbidity,treatment,and prognosis.Common types of non-Hodgkin's lymphoma in children or young people are Burkitt lymphoma,lymphoblastic lymphoma/leukemia,anaplastic large cell lymphoma,etc.However,paediatric-type follicular lymphoma(PTFL),paediatric nodal marginal zone lymphoma(PNMZL)and large B-cell lymphoma with IRF4 rearrangement(IRF4+LBCL)are rare and have a good prognosis.The 2016 WHO classification of tumours of haematopoietic and lymphoid tissues explicitly proposed these three rare types.The clinical and pathological features of the three types are overlapped to some extent,and they are easy to be confused with the corresponding type of adult lymphoma,so the differential diagnosis is very important.However,there are few relevant research reports at home and abroad,and limited materials for reference and study.People's understanding of of these diseases still needs to be improved.This study mainly collected cases from the First Affiliated Hospital of Zhengzhou University to retrospectively analyze the clinical and pathological characteristics of these three diseases,so as to improve the understanding of these three diseases and avoid missed diagnosis,misdiagnosis and overdiagnosis.Methods1.The cases of PTFL,PNMZL,and IRF4+LBCL diagnosed by the Department of Pathology between January 2015 and December 2019 in the First Affiliated Hospital of Zhengzhou University were collected and divided into Group 3:there were 9 cases of PTFL,4 cases of PNMZL,and 3 cases of IRF4+LBCL.2.The clinical data of 3 cases were collected,and the histology,immunophenotype and molecular characteristics of all cases were reviewed and the patients were followed up.Results1.All the 9 patients with PTFL were male,with a median age of 15 years old,and presented with enlarged lymph nodes in the head and neck region.None of the 9 patients were accompanied by B symptoms.8 patients were stage IA according to Ann Arbor staging and 1 patient was stage ?A.Histologically,PTFL was characterized by large and irregular follicular structures,with thin or absent mantle zones.There was no pole in the center,and the starry sky phenomenon is obvious.The neoplastic cells were uniform,medium-sized blastic cells with less cytoplasm,round or oval nucleus,and insignificant nucleoli.Neoplastic cells expressed B cell markers CD20 and germinal center markers CD 10 and BCL6,most of them did not express BCL2,while a few of them could be weakly expressed,and the proliferation index of neoplastic cells was high.Monoclonal rearrangement of Ig gene was found in neoplastic cells of all 9 cases.The BCL2 gene was not broken in 3 cases by FISH.Two patients received chemotherapy after resection of the disease,which were 2 cycles of R-CHOP program and 5 cycles of Hyper-CVAD program,and five patients only received the resection of the lesion,all of whom were free of the disease at present.2 cases were lost to follow-up.2.The 4 patients with PNMZL were all males,with a median age of 17 years.The onset sites were located in the lymph nodes of the head and neck.None of the 4 patients had B symptoms,and the Ann Arbor stage was IA.The histology of PNMZL was usually characterized by the widening of the interfollicular marginal region,with large follicular structure and a seemingly progressive transforming germinal center.The neoplastic cells are mostly mononucleoid B cells,with abundant and shallow cytoplasm,round or irregular nuclei,and inconspicuous nucleoli.The neoplastic cells expressed B cell marker CD20,half of the cases were accompanied by CD43 positive expression,BCL2 was often positive,germinal center markers CD 10 and BCL6 were mostly negative,and neoplastic cell proliferation index was low.Monoclonal rearrangement of Ig gene was found in all 4 tumor cells.One patient only received resection of the lesion,and was free of the disease at present.The remaining 3 cases were lost to follow-up.3.There were 3 patients with IRF4+LBCL,2 females and 1 male,with a median onset age of 19 years old.None of the 3 patients were accompanied by symptoms of B,and the Ann Arbor stage was IA-IIA.IRF4+LBCL histologically presents diffuse or follicular nodular growth of lymphoid tissue,with moderate to large neoplastic cells,less cytoplasm,slightly irregular nuclei,and some basophilic nucleoli.All neoplastic cells were positive for CD20,CD 10 and BCL6 were often positive,MUM1 was strongly positive,and BCL2 was also positive,and the proliferation index of neoplastic cells was high.The IRF4 gene was broken in 2 cases by FISH,and 1 case was accompanied by the BCL6 gene break.Two patients received 5-8 cycles of R-CHOP chemotherapy after resection of the lesion,and all of them survived.1 case was lost to follow-up.ConclusionPTFL,PNMZL and IRF4+LBCL are all rare mature b-cell lymphomas that often occur in children or young people.They all tend to occur in the head and neck region,with early stage and good prognosis.PTFL and PNMZL are more common in male cases,often manifested as isolated lymph node lesions in the head and neck.Observation and follow-up after resection seems to be a suitable treatment.IRF4+LBCL often occurs in the pharyngeal lymphatic ring and head and neck lymph nodes,the neoplastic cells diffusely and strongly expressed MUM1,accompanied by IRF4 gene rearrangement,and the prognosis was good after chemotherapy.Attention should be paid to the differentiation between the three and the adult corresponding types of diseases and the differential diagnosis among the three,to avoid missed diagnosis,misdiagnosis,overdiagnosis and overtreatment.