Malaria masquerading as relapse of Hodgkin's lymphoma on contrast enhanced 18F-fluorodeoxyglucose positron emission tomography/computed tomography: A diagnostic dilemma
The present case report is about a 22-year-old male patient who presented with enlarged right cervical lymph node. Biopsy revealed-Hodgkin's lymphoma (mixed cellularity). 18F-FDG PET/CECT performed for staging revealed metabolically active lymph nodes on either side of the diaphragm [, broken arrows], enlarged spleen with multiple hypodense hypermetabolic, lesions [, arrow] (SUVmax= 9.4; Spleen SUVmax/liver SUVmax ratio = 3.76) and bone lesion. He was then given 6 cycles of chemotherapy and 18F-FDG PET/CECT was done for response evaluation. PET/CT showed complete metabolic response, with normal spleen uptake [, 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, relapse was suspected and 18F-FDG PET/CECT was advised. PET/CT revealed enlarged spleen with diffusely increased FDG uptake [Figure –, 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). The patient was then started on anti-malarials with complete clinical improvement. Follow-up PET/CT after 7 months revealed normalization of size and 18F-FDG uptake of spleen [, arrow] (SUVmax= 3.0; Liver SUVmax= 2.7 S/L ratio = 1.1). This clinical case can be easily misinterpreted as lymphoma relapse. Hence, malaria and other relevant (endemic) infective possibilities (Kala-Azar etc.) should be considered and further investigation, if warranted, should be advised.