Fig. 1Primary effusion lymphoma (PEL). (A) Axial computed tomography scan shows pleural effusion of the right hemithorax with pleural enhancement. No marked parenchymal lesion is identified in either lung, apart from passive atelectasis owing to the effusion. Neither lymphadenopathy nor organomegaly is observed. (B) PEL cells show anaplastic/plasmablastic cytological features (cell block). (C) Cytospin showing large anaplastic tumor cells with features of plasmacytoid or immunoblastic features (Wright stain). (D) A subset of PEL cells is positive for CD138. Human herpes virus 8 can be identified in PEL cells by performing polymerase chain reaction (E) and immunocytochemistry (F) to detect latent nuclear antigen 1 on a cell block.
Fig. 2Solid primary effusion lymphoma (Solid PEL) tumor. (A) Starry-sky pattern. (B) Numerous mitoses. (C) Solid PEL cells, like PEL cells, show anaplastic/plasmablastic cytologic features, and some resemble Reed-Sternberg cells. (D-F) Immunohistochemical studies reveal that the tumor cells are CD20-negative (D), CD138-positive (E), and human herpes virus 8-positive (labeling for latent nuclear antigen 1) (F).
Fig. 3Human herpes virus 8-negative effusion-based lymphoma. (A) A chest computed tomography scan reveals a large amount of pleural effusion. Pleural enhancement is characteristically observed on both sides of the chest. Mediastinal lymphadenopathy is also observed. Massive ascites with multiple lymphadenopathy is sometimes detected. (B, C) The effusion contains large pleomorphic cells with large blastic nuclei (Giemsa stain). Tumor cells are large, immunoblastic or plasmablastic (D), and express the B-cell-associated antigen CD20 (E).
Fig. 4Pyothorax-associated lymphoma. (A) Two masses are located in the middle to lower right hemithorax. The larger of the two masses shows fluid attenuation and air bubbles, which is consistent with chronic empyema. Abutting the superomedial side of this mass is a smaller heterogeneously enhanced solid mass. The left lung is unremarkable, and mediastinal lymphadenopathy is not observed. (B) The lymphoma cells are morphologically similar to diffuse large B-cell lymphoma, not otherwise specified, with centroblastic or immunoblastic appearances. (C) The tumor cells express CD20. (D) Cytologically, the tumor cells are markedly pleomorphic (Papanicolaou stain).
Table 1.Main differential diagnoses of primary effusion lymphoma1,2,9,29,32
|
Primary effusion lymphoma |
Burkitt lymphoma |
Plasmablastic lymphoma |
HHV8-negative effusion-based lymphoma |
Pyothorax-associated lymphoma |
Demographic characteristics |
Young or middle-aged HIV+ (majority) |
Endemic: childhood |
Median age around 50 yr, mainly adult |
Older (median age 70 yr) |
HIV-elderly, male predominant, with a long history of pyothorax or chronic pleuritis |
Sporadic: children, young adults |
HIV+ or other immunodeficiency |
HIV-(95.1%), and non-immunocompromised anti-HCV (26.5%) |
Immudeficiency-associated |
Anatomic site |
Body cavities |
Extranodal; HIV+ patients may present with a lymphomatous effusion with plasmacytoid differentiation |
Extranodal; most commonly oral cavity; body cavities - rarely involved |
Body cavities |
Tumor mass localized in the body surface, and lymphomatous effusion is rare |
HHV8 |
(+) |
(-) |
(-) |
(-) |
(-) |
EBV |
(+) (majority) |
(+/-) (+) mainly endemic |
(+) (60-75%) |
(+) (30%) |
(+) (most cases) |
Immuno-phenotype |
CD20(–), CD19(–), CD79a(–), CD38(+), CD138(+), CD45(+/–), CD30(+/–) |
CD20(+), CD19(+), BCL6(+), CD10(+), BCL2(–), CD30(–), sIgM+, cIgM+ |
CD20(–), CD79a+(50-85%), CD38(+), CD138(+), CD19(–), CD45(–), CD30(–/+), cIgG+(50-70%) |
CD20(+) (majority), CD19(+), CD138(–/+), CD30(–/+) |
CD20(+) (majority), CD19(+), CD138(–/+), aberrant expression of T-cell markers |
Prognosis |
Poor; median survival <6 mo |
Endemic, sporadic - highly aggressive but curable |
Poor; median survival <1 yr |
Variable Median survival 10 mo |
5-yr survival 20-35% |
IgH |
Clonal |
Clonal |
Clonal |
Clonal |
Clonal |
Other genetic features |
No recurrent chromosomal abnormalities |
C-MYC gene rearrangement |
Subset with t(8;14)(q24;q32) or MYC-IgH |
Complex karyotypic anomalies in 50% |
Complex karyotypic anomalies TP53 mutations (70%) |