Introduction Pulmonary embolism (PE) is one of the commonly encountered diagnoses in the emergency department and poses a significant threat to patients’ lives. However, there remains a diagnostic challenge due to the wide range of presentations, some of which can be atypical and thus misleading. In fact, pulmonary embolism has recently been named in the literature as the great masquerader. In this article we discuss a case of pulmonary embolism that presented with abdominal pain. Case Presentation We report a case of a 25-year-old female with a past medical history of hypertension and end stage renal disease on regular hemodialysis, who presented to the emergency with sudden onset, severe left sided flank pain radiating to the chest for 2 days. She noted that the pain was constantly present and worsened with breathing. She also reported black stools and one episode of spitting blood. She denied the presence of other symptoms. Her heart rate was fluctuating between 100-110 beats per minute, but otherwise her vitals were within normal limits. Physical examination revealed a soft, non-distended and non-tender abdomen. Lab work was significant for a C-reactive protein level of 311 mg/L and D-Dimer level of 7.19 mcg/mL. Chest X-ray showed a left lower lobe infiltrate with minimal pleural effusion. A computed tomography of the chest was ordered in view of her tachycardia and high D-dimer level. Results of the imaging revealed an acute pulmonary embolism of the left lower lobe segmental artery associated with pulmonary infarction. Conclusion: A missed diagnosis of PE can lead to severe consequences, warranting a high index of suspicion. In this case, the patient’s initial complaints of abdomen pain masked the underlying condition. Moreover, our patient lacked the risk factors for a pulmonary embolism and had a well’s score of 1.5 only, that was attributed to her tachycardia. She also had other symptoms that clouded her presentation and was pointing more towards an abdominal etiology. This goes to say that while pattern recognition aids in the medical decision-making process, it’s important for the physician to keep an open mind when there’s uncertainty. A high index of suspicion can significantly impact patient outcomes.

Keywords: Pulmonary embolism, Pulmonary Infarction, Abdominal Pain, Clinical decision-making.