Clinical Practice and Cases in Emergency Medicine

Introduction: Morel-Lavallée lesions are closed, soft tissue degloving injuries that occur when shearing forces separate the subcutaneous tissue from the underlying fascia. This creates a potential space for hemolymphatic fluid accumulation. Morel-Lavallée lesions are frequently under-reported and often misdiagnosed as hematomas or abscesses, leading to potential mismanagement. While magnetic resonance imaging (MRI) is considered the gold standard for diagnosis, point-of-care ultrasound (POCUS) has been shown to be an effective adjunct that can rapidly confirm sonographic features consistent with Morel-Lavallée lesions, support MRI-established findings, and guide procedural intervention in the emergency department (ED) setting.

Case Report: We describe a 20-year-old woman presenting to the ED with persistent right-sided hip pain two months after a pedestrian–motor vehicle collision. Initially misdiagnosed as a hematoma, an outpatient follow-up MRI identified a large Morel-Lavallée lesion, with POCUS confirming subcutaneous anechoic fluid collection in the ED. Ultrasound-guided aspiration yielded 150 mL of serosanguinous fluid, with real-time imaging confirming decompression. Laboratory analysis demonstrated elevated red blood cell and nucleated cell counts consistent with Morel-Lavallée lesion.

Conclusion: This case highlights the integrated diagnostic and therapeutic role of point-of-care ultrasound as an adjunct to MRI, confirming sonographic features of a Morel-Lavallée lesion, guiding aspiration, and providing real-time postprocedural assessment within a single ED encounter in a patient presenting two months after injury.