Morphological and immunophenotypic features of follicular lymphoma by abdominal cavity puncture biopsy

WU Ting; ZHOU Xiao-ge; SHAO Rui

doi:10.3969/j.issn.1007-8096.2025.01.007

Abstract：Objective To investigate the clinical features,pathologic features,immunophenotype and differential diagnosis of follicular lymphoma(FL)in abdominal cavity puncture biopsy.Methods The clinical,morphological and immunophenotypic characteristics of 183 cases of follicular lymphoma diagnosed by abdominal cavity puncture biopsy were retrospectively analyzed.Results There were 87 males and 96 females,with a male to female ratio of 1∶1.1.The age range was 22-89 years,and the median age was 48 years.There were 66 cases in retroperitoneum,65 cases in abdominal lymph nodes,52 cases of other parts in the abdominal cavity.Histological gradeing showed there were 158 cases(86.34％)in low grade,including 33 cases(18.03％)in grade 1,102 cases(55.74％)in grade 1-2,23 cases(12.57％)in grade 2,and 18 cases(9.84％)in grade 3A,of which 7 cases were accompanied by diffuse large B-cell lymphoma(DLBCL)transformation.There were 2 cases of grade 3B(1.09％)and 5 cases(2.73％)of mixed type of low-grade and high-grade.That is,some of them were grade 1-2 or 2,mixed with different proportions of grade 3A area.Under the microscope,the tumor cells were composed of centrocytoid-like cells and centroblast-like cells.CD20,CD79α and Pax-5 were highly expressed in tumor cells,while CD3 and CD5 were negative.CD10,BCL-6 and BCL-2 were expressed in neoplastic follicular areas.CD21 and CD23 showed the presence of follicular dendritic cell(FDC)networks in the follicular region,and FDC networks were ruptured in grade 3.CD43,MUM-1,CyclinD-1 and EBER were negative.CD38 strong positive cells in germinal center disappeared or decreased,and the proliferation index of Ki-67 was differentially expressed with different grades.Conclusion This group of abdominal puncture of follicular lymphoma has its unique characteristics.It usually occurs in middle-aged and elderly people,but does not occur in children,and often involves retroperitoneal and abdominal lymph nodes.The follicle-dominated growth pattern is rare,and low-grade FL is the most common type,and CD 10 is highly expressed.Familiarity with these features is helpful for the diagnosis of FL in abdominal cavity puncture biopsy.