This criterion is based on exclusion of three entities that have been recognized as part of these subtypes: Primary Cutaneous CD4-Positive Small/Medium T-Cell Lymphoma (CD4+ SMTL), Primary Cutaneous CD8-Positive Aggressive Epidermotropic T-Cell Lymphoma (CD8+ AECTCL), and Primary Cutaneous Gamma/Delta T-Cell Lymphoma (CGD-TCL) [2, 3]. This evidence concerns the gene CD4 and T-cell non-Hodgkin lymphoma.