The malignant transformation of lymphocytes can result in malignant lymphomas. These tumors arise in the primary (thymus, bone marrow) or secondary (spleen, lymph nodes, mucosa associated lymphoid tissue) lymphoid organs. Clinically, they are multifold and can behave as indolent, slowly-growing tumors or as fast-growing aggressive masses. B lymphoid-derived malignant lymphomas are distinguished in Hodgkin's (also known as Hodgkin's disease, HD) and non-Hodgkin's lymphomas (NHL). Specific genetic and molecular alterations can be found associated to HD and NHL, some of which characteristically mark a particular subtype. In Figure A, hematoxylin/eosin staining of a normal follicle containing a germinal center surrounded by a darker mantle zone is shown in comparison with figure D showing a deranged lymph node structure with cells highly positive for Cyclin D1 (immunohistochemical staining) in a case of mantle cell lymphoma.
