Atypical Presentation of Pulmonary Embolism: Flank Pain as the Sole Symptom in a PERC-Negative Patient–The Role of POCUS in Early Detection

Pulmonary embolism (PE) is a potentially life-threatening condition with diverse clinical presentations. While dyspnea and pleuritic chest pain are the hallmark symptoms, atypical presentations such as isolated flank pain can obscure timely diagnosis. We report a case of a 39-year-old male smoker who presented with left-sided flank pain exacerbated by deep inspiration. Despite meeting Pulmonary Embolism Rule-Out Criteria (PERC), the crucial role of lung point-of-care ultrasound (POCUS) in identifying localized B-lines and an elevated D-dimer prompted CT pulmonary angiography, confirming segmental PE. This case underscores the diagnostic utility of POCUS and highlights the limitations of PERC in atypical presentations.