Unusual Distal Leg Presentation of Morel-Lavallée Lesion: Case Report with Review of Diagnostic and Management Strategies

A Morel-Lavallée lesion is a rare post-traumatic closed degloving injury defined by chronic fluid collection between subcutaneous tissue and fascia. We report a case involving a 42-year-old immunocompromised man with persistent swelling of the right leg after a fall 18 months earlier. The lesion was fluctuant and mildly tender, with no skin changes. Ultrasound revealed a complex cystic mass (6.6 × 4.2 × 1.0 cm) in the deep subcutaneous plane, raising suspicion for a Morel-Lavallée lesion. MRI confirmed a fluid collection overlying the fascia near the ankle. Orthopedic evaluation recommended percutaneous aspiration and compressive bandaging for 4–6 weeks to close the dead space, with surgery reserved for refractory cases. This report highlights the need to recognize Morel-Lavallée lesions long after trauma, as early identification prevents mismanagement. We also review the prevalence, diagnostic challenges, and management options for this condition.