Pathological characteristics of angioimmunoblastic T cell lymphoma with bone marrow involvement / 临床与实验病理学杂志

ABSTRACT

Purpose To explore the pathological features of angioimmunoblastic T-cell lymphoma(AITL)with bone marrow involvement and to improve awareness of bone marrow infiltration in AITL.Methods The tissue morphology of 32 cases of AITL with bone marrow involvement was retrospectively analyzed.Im-munohistochemistry using the EnVision method and ten-color flow cytometry were conducted to detect AITL-related immune markers.T cell clonality was analyzed through T cell receptor(TCR)gene rearrangement.Results The predominant pat-terns of tumor cell infiltration were nodular(20/32,62.5％)and interstitial or small clusters(10/32,31.3％).The nodules showed a mixture of cellular components.In some cases,the fo-ci contained a mixture of cells with characteristic"granuloma-toid"changes.The tumor cells were mainly small to medium-sized lymphocytes with inconspicuous atypia.Some cases showed plasma cell proliferation.19 cases were subject to immunohisto-chemical staining,which revealed a low count of CD4-positive T cells,with an average of 8.4％.The positive rates of T follic-ular helper cells(TFH)markers were as follows:CD10(7/14,50.0％),BCL6(6/19,31.6％),PD-1(13/19,68.4％),and CXCL13(13/19,68.4％).In most cases,tumor cells showed co-expression of PD-1 and CXCL13,but the number of positive cells was less than 1％.Flow cytometry analysis was performed in 24 cases,among which 22 cases all consistently expressed cytoplasmic CD3(cCD3),CD5,CD4,and CD2,with varying degrees of CD10 expression.In some cases,there was a lack of expression of surface CD3(sCD3)(12/22,54.5％),while there was a lack of expression of CD7(8/22,36.4％).and no abnormal T cells were found in 2 cases.TCR gene rearrangement analysis was performed in 7 cases,with 3 cases showing TCR clonality.Conclusion AITL with bone marrow involvement exhibits a lower proportion of tumor cells and less atypia,making it prone to misdiagnosis.The presence of lymphocytic foci with mixed cellular components in the bone marrow can indicate bone marrow involvement in AITL.Flow cy-tometry detection of abnormal T cells(double positive for CD4 and CD10)strongly suggests bone marrow infiltration in AITL.A comprehensive diagnosis of bone marrow involvement in AITL re-quires consideration of bone marrow biopsy,flow cytometry,and TCR gene rearrangement analysis.