CASE PRESENTATION: A 61-year old female with past history of hypogammaglobinemia, recurrent bronchitis, obstructive sleep apnea and unprovoked left lower lobe pulmonary embolism five prior to admission. She presented to Emergency Department with acute onset chest pain. Work up for acute coronary syndrome was negative. Subsequently she underwent ventilation perfusion lung scan which revealed left lower lobe mismatched perfusion defect suggestive of acute pulmonary embolism. Due to lack of risk factors and negative hypercoagulable work up, patient underwent CT angiogram of chest which showed no evidence of pulmonary arterial filling defects but a diminutive left lower lobe pulmonary artery with decreased overall size of left hemithorax, peripheral scarring, atelectasis consistent with SJS. Further history revealed that patient had history of recurrent respiratory tract infection as childhood. We hypothesized that her history of left lower lobe pulmonary embolism was mostly likely due to underlying hypoplastic left pulmonary artery and not true pulmonary thromboembolic disease. She was treated symptomatically for musculoskeletal pain and discharged to follow up with pulmonary clinic.