<unk>  were classified by the World Health Organization, 2017 as a sub-grouping of several distinct but rare lymphomas in which the malignant cells are B-cell lymphocytes that have become plasmablasts, i.e. immature plasma cells. Normally, B-cells take up foreign antigens, move to the germinal centers of secondary<unk>  organs such the spleen and lymph nodes, and at these sites are stimulated by T-cell lymphocytes to differentiate (i.e. change their cell type) into plasmablasts and thereafter mature plasma cells. Plasmablasts, and to a greater extent, plasma cells make and secrete antibodies that bind the antigens to which their predecessor B-cells were previously exposed (see plasma cell<unk> . Antibodies function, in part, to neutralize harmful bacteria and viruses by binding antigens that are exposed on their surfaces. Due to their malignant nature, however, the plasmablasts in<unk>  do not mature into plasma cells or form antibodies but rather uncontrollably proliferate in and damage various tissues and organs. The individual lymphomas in this sub-group of malignancies have heterogeneous clinical, morphological, and gene findings that often overlap with other members of the sub-group. In consequence, correctly diagnosing these lymphomas has been challenging. Nonetheless, it is particularly important to diagnose them correctly because they often have very different prognoses and treatments. The<unk><unk>  with plasmacytic<unk>  are: * 1)<unk>  lymphoma: The most common of these<unk><unk> . * 2)<unk>  plasma cell lymphoma or<unk>  plasmacytoma: A<unk> <unk> that disseminates widely like the plasma cell lesions in multiple myeloma or is localized like the plasma cell lesions in plasmacytoma. * 3) Primary effusion lymphoma, human herpes virus-positive: Also termed primary effusion lymphoma, type I; it is usually characterized by manifesting effusions in body cavities. * 4) Primary effusion lymphoma, human herpes virus-negative: Also termed primary effusion lymphoma, type II; it is characterized by having effusions in body cavities. * 5) Anaplastic lymphoma kinase-positive large B-cell lymphoma: An anaplastic large cell lymphoma in which the malignant cells have<unk>  features and a distinguishing mutation in the anaplastic lymphoma kinase gene. * 6) Human herpesvirus 8-positive diffuse large B-cell lymphoma, not otherwise specified: This<unk> <unk> usually arises from the lymphoproliferative disease, idiopathic multicentric Castleman disease. Except for human herpesvirus 8-positive diffuse large B-cell lymphoma, not otherwise specified, these<unk><unk>  are often associated with Epstein-Barr virus infection of the malignant<unk>  cells. In cases so infected, the<unk> <unk> may result, at least in part, from this viral infection and therefore can be considered as examples of the Epstein-Barr virus-associated lymphoproliferative diseases.
Lymphoid neoplasms with plasmablastic differentiation
Diffuse large B-cell lymphoma associated with chronic inflammation
Large B-cell lymphoma arising in HHV8-associated multicentric Castleman's disease
Persistent polyclonal B-cell lymphocytosis
Splenic lymphoma with villous lymphocytes
Indolent T cell lymphoproliferative disorder of the gastrointestinal tract
Embryonal tumour with multilayered rosettes
Thymoma-associated multiorgan autoimmunity