flurodeoxyglucose ( f - fdg ) positron emission tomography / computed tomography ( pet / ct ) has become the imaging modality of choice for initial staging , follow - up and treatment response assessment in patients with hodgkin 's lymphoma and has proved superior to contrast enhanced ct ( cect ) in these settings .
f - fdg pet / ct has accuracy of almost 100% in diagnosing primary splenic involvement during initial staging of lymphoma . however , in the post - therapy setting its role for evaluation of secondary splenic involvement is limited .
one of the pattern of splenic activity that help to detect splenic involvement on pet / ct is diffusely increased f - fdg uptake greater than that in the liver and bone marrow with or without corresponding ct lesions . in this context , we report a case of a patient with hodgkin 's lymphoma in remission presenting with f - fdg avid splenomegaly .
the present case report is about a 22-year - old male patient who presented with enlarged right cervical lymph node .
f - fdg pet / cect performed for staging revealed metabolically active lymph nodes on either side of the diaphragm [ figure 1a , broken arrows ] , enlarged spleen with multiple hypodense hypermetabolic , lesions [ figure 1a , arrow ] ( suvmax= 9.4 ; spleen suvmax / liver suvmax ratio = 3.76 ) and bone lesion .
he was then given 6 cycles of chemotherapy and f - fdg pet / cect was done for response evaluation .
pet / ct showed complete metabolic response , with normal spleen uptake [ figure 1b , arrow ] ( spleen suvmax= 2.5 , liver suvmax= 2.6 s / l ratio = 0.96 ) . at 1-year
later routine follow - up the patient complained of mild fever , lethargy and listlessness . in view of previous history of hodgkin 's lymphoma ,
pet / ct revealed enlarged spleen with diffusely increased fdg uptake [ figure 2a  c , arrow ] ( suvmax= 5.3 ; liver suvmax= 2.3 s / l ratio = 2.30 ) .
the first differential in the given clinical scenario was splenic relapse of lymphoma , however , a second differential diagnosis of some infective / inflammatory process was considered .
on further evaluation , peripheral smear showed evidence of malaria parasite infection ( plasmodium vivax ) .
follow - up pet / ct after 7 months revealed normalization of size and f - fdg uptake of spleen [ figure 2d , arrow ] ( suvmax= 3.0 ; liver suvmax= 2.7 s / l ratio = 1.1 ) .
hence , malaria and other relevant ( endemic ) infective possibilities ( kala - azar etc . ) should be considered and further investigation , if warranted , should be advised .
f - flurodeoxyglucose ( f - fdg ) positron emission tomography/ computed tomography ( pet / ct ) done for staging and response evaluation .
( a ) staging maximum intensity projection ( mip ) pet image showing multiple metabolically active lymph nodes in thorax , abdomen and pelvis ( broken arrows ) with splenic ( arrow ) and bone lesion ( left femur ) .
( b ) mip pet image done for response evaluation demonstrates complete metabolic response with normal splenic fdg uptake ( arrow ) .
physiological gastric fdg uptake noted ( bent arrow ) f - flurodeoxyglucose ( f - fdg ) positron emission tomography / computed tomography ( pet / ct ) done for recurrence detection and follow - up .
( a - c ) follow - up pet / ct performed 1 year after chemotherapy showing enlarged spleen with diffusely increased fdg uptake ( arrow ) .
( d ) maximum intensity projection pet image performed after anti - malarial therapy , showing normalization of size and fdg uptake of spleen ( arrow ) . ( a and d )
focal fdg uptake noted in the pelvis is due to urinary fdg activity in the left ureter ( curved arrows )
pet / ct is a useful modality for staging and restaging of hodgkin 's lymphoma with high sensitivity and specificity .
furthermore , it is a sensitive modality for early detection of relapse in asymptomatic patients making surveillance f - fdg pet / ct clinically important .
splenic uptake on f - fdg pet can be due to a wide variety of causes such as lymphoma , anemia , granulocyte colony stimulating factor treatment , beta - thalassemia , inflammation and infections .
splenic uptake , greater than hepatic uptake , is a relatively reliable indicator of lymphomatous involvement of the spleen , in the absence of recent cytokine administration . in early stage hiv infection , diffusely increased splenic uptake is noted due to reactive stimulation of b - cells in the spleen .
post - therapeutic reactive splenic uptake is also noted after administration of granulocyte colony - stimulating factor for myelosuppression or high - dose interferon - alpha-2b adjuvant therapy for melanoma . until date , only a single report by liu et al . have demonstrated f - fdg uptake in spleen in case of malaria .
 18flurodeoxyglucose ( 18f - fdg ) positron emission tomography / computed tomography ( pet / ct ) is nowadays routinely used in management of lymphoma patients . 
 we here present a case of hodgkin 's lymphoma which showed 18f - fdg avid splenomegaly on pet / ct done for clinically suspected relapse . 
 further evaluation by peripheral smear examination revealed malaria . 
 the patient was then started on anti - malarial medications and follow - up pet / ct revealed resolution of hypermetabolic splenomegaly . 
 this report highlights that in endemic regions malaria can cause 18f - fdg avid splenomegaly and might mimic relapse of lymphoma . 