This weakening is ascribed to KSHV/HHV8 infection that is commonly further promoted by concurrent human immunodeficiency virus (i.e. HIV) infection, prior organ transplantation, the decline in immunity that develops with aging, and/or cirrhosis of the liver due to hepatitis B or C virus. The plasmacytoid cells in PEL are also commonly infected with the Epstein-Barr virus (i.e. EBV). EBV is a known cause of various Epstein-Barr virus-associated lymphoproliferative diseases including various B-cell lymphomas. However, the role of this virus in the development of PEL is not clear, although some studies suggest that EBV infection cooperates with KSHV/HHV8 infection to promote the development and/or progression of this disease.Formally, PEL is defined by the World Health Organization, 2016 as a KSHV/HHV8-positive and KSHV/HHV8-driven large B-cell lymphoma. This lymphoma also belongs to a group of lymphoid neoplasms with plasmablastic differentiation that involve malignant plasmablasts but differ from PEL in the types of tissues where they accumulate, the gene abnormalities they carry, and/or the predisposing conditions involved in their development. More than 50, 30, and 60% of all PEL cases, respectively, develop in individuals who already have KSHV/HHV8-positive Kaposis sarcoma, human herpesvirus 8-associated multicentric Castleman disease, and/or (especially in HIV-positive individuals) evidence of bearing EBV-infected plasmablasts.Primary effussion lymphoma is an extremely aggressive cancer that is highly resistant to various chemotherapy treatments. It has carried a median survival time of ~5 months, with overall survival rates at 1, 3, and 5 year of only 30, 18, and 17%, respectively.
In many cases, however, this high mortality reflects, at least in part, the lethality of its underlying predisposing diseases, particularly HIV/AIDS in HIV-infected individuals. New treatment strategies, including those directed at its underlying predisposing diseases, may improve the prognosis of PEL. Presentation
Individuals diagnosed with PEL most commonly (>33% of all cases) present with advanced Stage III or IV disease. They are predominately males with a median age of 42 years if they are infected with HIV and 73 years if they are not so infected. Some one-third to one-half of these individuals have a history of Karposis sarcoma, less commonly of multicentric Castleman disease, and/or rarely of immune deficiency due to organ transplantation, hepatitis complicated by cirrhosis caused by hepatitis B or C viral infection, or of old age. PEL occurring in the elderly generally occurs in EBV-negative individuals residing in the Mediterranean region. Individuals with the cavitary form of PEL present with symptoms due to effusions in the pleural cavity (e.g. shortness of breath), pericardium (e.g. chest pain/discomfort, hypotension, shortness of breath), peritoneal cavity (e.g. abdominal swelling), or, much less often, joints (e.g. swelling), the epidural space (e.g. central nervous system symptoms), or breast implants (e.g. breast swelling/pain/malformation). While most cases of classical PEL involve one cavitary site, some individuals present with two or more sites of cavitary involvement. Individuals with extracavitary PEL present with lesions in the lung, central nervous system, gastrointestinal tract, and/or lymph nodes. Gastrointestinal track lesions often occur as multiple lymphoid polyps in the large intestine.