Overview of cutaneous non-Hodgkin’s lymphoma The skin immune system has a unique structure and immune function, consisting of epidermal keratinocytes (KCs), epidermal Langerhans (LCs), dermal Dendritic Cells (DDCs), lymphocytes (especially recirculating epidermotropic T Langerhans cells and dendritic cells have a key role in the processing and delivery of antigens. Epidermal keratinocytes produce cytokines that interact with T cells and enhance the T lymphocyte-mediated immune response in the skin. Skin-derived T lymphocytes are “nesting” and nest primarily in the skin, called epidermotropic T lymphocytes; lymphocytes originating from peripheral lymph nodes nest primarily in peripheral lymph nodes; lymphocytes originating from Mucosa-Associated Lymphoid Tissue (MALT) nest primarily The lymphocytes from Mucosa-Associated Lymphoid Tissue (MALT) were mainly located in peyer nodes and mesenteric lymph nodes. Different organ-associated lymphomas not only have their own unique clinical manifestations, but also differ in the expression of adhesion molecules, oncogene products and viral DNA sequences. Therefore, there is an increasing tendency to classify malignant lymphomas by their organ and tissue of origin, such as Lymph Node Malignant Lymphoma (LNML), MALT-ML, or primary cutaneous malignant lymphoma (PCML).