Primary cutaneous B-cell lymphomas

Cutaneous lymphomas (CL) are a heterogeneous group of neoplasias that are characterized by an accumulation of mononuclear, mostly lymphocytic cells in the skin (Burg et al, J Dtsch Dermatol Ges 4:914-933, 2006). Cutaneous lymphomas are the second most prevalent extranodal non-Hodgkin lymphomas (after gastrointestinal), representing approximately 19 % of extranodal non-Hodgkin lymphomas. Primary cutaneous B-cell lymphomas represent less than one third of cutaneous lymphomas (Willemze et al, Blood 105:3768-3785, 2005; Bradford et al, Blood 113:5064-5073, 2009). Distinguishing between low-grade CBCL and reactive B-cell pseudolymphomas can be quite difficult; even clonality studies cannot with certainty separate the two entities (Dummer et al, Ann Oncol 19(Suppl 2):ii72-ii76, 2008). The World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) has categorized primary cutaneous B-cell lymphomas to three main subtypes: primary cutaneous follicle center lymphoma (PCFCL), primary cutaneous marginal zone lymphoma(PCMZL), and primary cutaneous diffuse large B-cell lymphoma (DLBCL) ("leg type” and "others”) (Willemze et al, Blood 105:3768-3785, 2005).