<h4>Background</h4>Sézary syndrome (SS) is an aggressive leukemic variant of cutaneous T-cell lymphoma (CTCL) with distinct clinical and biological features compared to rarer entities such as primary cutaneous CD8<sup>+</sup> aggressive epidermotropic cytotoxic T-cell lymphoma (PCAECTCL). This evidence concerns the gene CD8A and primary cutaneous T-cell non-Hodgkin lymphoma.