A rare case of massive pulmonary embolism is presented in an oligosymptomatic teenager with predisposing factors. Computed tomography pulmonary angiography supported by three-dimensional reconstruction was diagnostic. The embolus qualified as massive by conventional anatomical guidelines, but as low risk by more recent functional criteria. Functional assessment has complemented morphologic assessment for risk stratification in adult patients. Such evidence is scarce in pediatrics. The patient underwent surgical embolectomy, followed by prophylactic anticoagulation, without further events. Diagnostic and management challenges are discussed.