primary effusion lymphoma ( pel ) is a rare form of non - hodgkin 's lymphoma characterized by malignant fluid accumulation in the absence of lymphadenopathy . typical sites of accumulation include pleural , pericardial , and ascites fluid .
pel is associated with immunodeficiency states such as acquired immunodeficiency syndrome ( aids ) and infectious etiologies such as human herpes virus 8 ( hhv8 ) . the world health organization ( who ) uses the pel term for only hhv - related pel . in our case ,
the term hhv8-unrelated pel - like lymphoma has been used in the literature to describe such cases .
we present the case of a 71-year - old female with no significant past medical history who originally presented to the clinic with shortness of breath , abdominal bloating , and lower extremity edema .
post - pericardiocentesis the patient reported only residual orthopnea and night cough when lying down .
analysis of the aspirated pericardial fluid revealed monoclonal b - cell lymphocytes compatible with diffuse large b - cell lymphoma , which prompted staging positron emission tomography / computed tomography ( pet / ct ) . of note ,
immunologic blood work was negative for hepatitis a , hepatitis b , and hepatitis c infection .
serum polymerase chain reaction ( pcr ) was negative for cytomegalovirus ( cmv ) and epstein  barr virus ( ebv ) .
the 18-flourodeoxyglucose pet / ct ( 18-f fdg pet / ct ) was performed using 19.6 mci of intravenously administered radiotracer on a ge discovery ste pet / ct scanner ( ge healthcare , waukesha , wi , usa ) .
the patient was imaged 1 and 2 h postinjection . the pet / ct demonstrated uniformly increased radiotracer uptake in a moderate pericardial effusion ( standardized uptake value ( suv ) maximum 3.2 ) , which increased in metabolic activity on delayed imaging ( suv maximum 3.6 ) .
of note , the activity was within the fluid density space of the pericardial effusion and not limited to solely the pericardium itself [ figure 1 ] .
additionally , there were moderate bilateral pleural effusions and abdominal ascites , which demonstrated similar persistent and uniform radiotracer uptake [ figures 2 and 3 ] [ table 1 ] .
these findings are compatible with malignant involvement , particularly given this patient 's history of prior pathology - proven malignant pericardial effusion .
axial pet / ct images demonstrate 18-f fdg radiotracer uptake in moderate pericardial effusion ( arrows ) .
pet = positron emission tomography , ct = computed tomography , 18-f fdg = 18-flourodeoxyglucose whole body mip .
coronal whole body mip image obtained 1 h after the intravenous injection of 19.6 mci 18-f fdg .
mip = maximum intensity projection , 18-f fdg = 18-flourodeoxyglucose ( a and b ) the 18f - fdg accumulation over time .
metabolically active bilateral pleural effusions ( crosshairs ) at ( a ) 1-h and ( b ) 2-h postinjection .
18-f fdg = 18-flourodeoxyglucose standardized uptake value maximum over time of note , the pet / ct also demonstrated no significant hypermetabolic cervical , thoracic , abdominal , or pelvic lymphadenopathy despite the above - described fdg - avid fluid collections [ figure 4 ] .
axial pet / ct images demonstrate 18-f fdg radiotracer uptake ( crosshairs ) in ( a ) abdominal and ( b ) pelvic ascites .
pet = positron emission tomography , ct = computed tomography , 18-f fdg = 18-flourodeoxyglucose the patient received chemotherapy and follow - up restaging pet / ct demonstrated interval resolution of the hypermetabolic pericardial , pleural , and peritoneal effusions [ figure 5 ] .
pel is a rare subtype of non - hodgkin 's lymphoma characterized by malignant effusions in the body cavities such as the pericardial , pleural , and peritoneal cavities in the absence of lymphadenopathy or organomegaly .
pel was first described in 1989 in a patient with hhv8 and human immunodeficiency virus ( hiv ) infection .
when pel occurs in the absence of hhv8 , the term hhv8-unrelated pel - like lymphoma has been used in the literature .
the described pet / ct findings in our case of hhv8-unrelated pel - like lymphoma are similar to the previously reported pet / ct findings in traditional pel .
therefore , the distinction between pel and hhv8-unrelated pel - like lymphoma requires analysis of the fluid and testing for the presence of hhv8 .
the distinction between these two closely related clinical entities is important because hhv8-unrelated pel - like lymphoma has a more favorable prognosis than traditional pel .
the b - cell markers obtained from flow cytometric analysis have also been found to be helpful in the differentiation between pel and hhv8-unrelated pel - like lymphoma .
the cells in pel are usually negative for b - cell markers such as cluster of differentiation ( cd)19 , cd20 , and cd79a . in our patient ,
we describe the pet / ct findings of hhv8-unrelated pel - like lymphoma , which has only once been previously reported .
the presence of malignant fluid accumulation in the absence of lymphadenopathy should raise suspicion of pel .
the imaging features of hhv8-unrelated pel - like lymphoma appear to be similar to previously reported pel pet / ct findings .
therefore , analysis of the fluid with particular attention to the presence of hhv8 is necessary to make this distinction , which is clinically significant because hhv8-unrelated pel - like lymphoma portends a more favorable prognosis compared with traditional pel .
 we present a 71-year - old female with human herpes virus 8 ( hhv8)-unrelated primary effusion lymphoma ( pel)-like lymphoma . 
 dyspnea and pericardial effusion led to pericardiocentesis , diagnosing diffuse large b - cell lymphoma . 
 she underwent positron emission tomography / computed tomography ( pet / ct ) , which demonstrated hypermetabolic pericardial , pleural , and ascites fluid without lymphadenopathy elsewhere . 
 malignant fluid in the absence of lymphadenopathy is a hallmark of pel . 
 pel is associated with immunodeficiency states such as acquired immunodeficiency syndrome ( aids ) and infectious agents such as hhv8 . 
 our patient had no such history and had not received immunosuppressive chemotherapy . 
 we present the pet / ct findings of this rare case of hhv8-unrelated pel - like lymphoma . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION