Cytokine storm is a poorly explained clinical entity caused by an undesired and 
aggrandized immune system response leading to unregulated activation of the 
proinflammatory cascade, often contributing to multisystem organ failure and 
even death. Its potentially diverse etiologies and sepsis-like presentation have 
made it even more challenging to diagnose, and so far, no well-established 
treatment protocol has been proposed. Its association with certain medications, 
especially with monoclonal antibodies, has well been reported in literature. To 
the best of our knowledge, so far, no previous case of cytokine storm associated 
with imatinib has been reported. We herein present a case report of a 
77-year-old male with a past medical history of hypereosinophilic syndrome who 
developed acute fatal cytokine storm following treatment with imatinib. This 
study highlights a life-threatening complication of the medication that may be 
underrecognized.