BCL6 and angioimmunoblastic T-cell lymphoma: Immunohistochemical (IHC) examination is critical to establish AITL diagnosis, neoplastic cells are typically positive for T cell markers as CD4, CD5, and CD2, as well as markers of TFH cells, such as CD10, CXCL13, ICOS, BCL6, and PD1 [16,17,18].