Primary cutaneous B-cell lymphomas and blastic plasmacytoid dendritic cell neoplasm: a short, updated review (Part II)

Primary cutaneous lymphomas (PCL) are neoplasms of the immune system, characterized by a proliferation of either T or B lymphocytes or rarely plasmacytoid dendritic cells that primary arise in the skin, without extracutaneous manifestations of the disease at presentation. In 2005, a joint World Health Organisation-European Organisation of Research and Treatment of Cancer (WHO-EORTC) classification for PCL was published. This classification has been incorporated, with a few modifications, into the new WHO classification of tumors of hematopoietic and lymphoid tissues published in 2008. In terms of cutaneous B-cell lymphomas, the WHO-EORTC classification for PCL recognizes three specific entities: cutaneous follicle center lymphoma, the cutaneous marginal zone lymphoma (MZL), and the cutaneous diffuse large B-cell lymphoma, leg type. In the WHO classification of 2008, the MZL has been included within the extranodal MZL of mucosaassociated lymphoid tissue. Moreover, a new third category of precursor of hematologic neoplasm including the blastic plasmacytoid dendritic cell neoplasm has been introduced.