What is non-Hodgkin's lymphoma?

Usually of B cell origin (T cell are much rare), present with widespread lymphadenopathy, B symptoms (fever, weight loss, night sweats). Spread non-contiguously and often involves extranodal sites. CD markers (used in immunohistochem and flow cytometry, B cells CD19 and 20, plasma cells CD138 k and lambda, CD3,5 for T cells)