Based on the histological features of the enlarged lymph node, with nodular expanding dendritic networks and high endothelial venules, combined with infiltrating CD4-positive atypical small T-lymphocytes with TFH phenotype, scattered CD30-and CD20-positive RS-like B-cells, and clinical signs of systemic lymphadenopathy with chylothorax and chylous ascites, the patient was diagnosed with AITL.
However, for AITL, identification of typical immunomorphological features such as proliferation of arborizing high endothelial venules and infiltration of atypical T-lymphocytes, negative PAX-5 immunostaining, and expression of CD3 and CD4 on a subset of RS-like B-cells can be used to avoid misdiagnosis [7, 14].