Misleading Chest Pain: Acute Coronary Syndrome or Lung Adenocarcinoma With Malignant Pericardial Effusion.

Chest pain is the most common presentation of acute coronary syndrome (ACS), but noncardiac causes should be considered when symptoms persist despite treatment or when other clinical features suggest an alternative diagnosis. We report a case of a 60-year-old woman with dyslipidemia who presented with chest pain, exertional dyspnea, and mild dry cough. Initial evaluations, including electrocardiogram and elevated troponin I levels, suggested a diagnosis of ACS. However, her symptoms did not settle with the initial treatment for ACS. Further investigations revealed moderate to massive pericardial effusion and cytology indicative of malignant cells. CT imaging showed a mass in the right lower lobe of the lung with associated bronchial obstruction, lung collapse, and sclerotic bone metastases. Bronchoscopy and biopsy confirmed the diagnosis of invasive adenocarcinoma of the lung. This case emphasizes the essential of considering a broad differential diagnosis, the importance of comprehensive diagnostic workup in patients with persistent chest pain, and stresses the role of interdisciplinary approaches in difficult clinical scenarios.