Morel-Lavallée Lesion of the Knee: A Case Report

Morel-Lavallée lesions are closed soft tissue injuries caused by a shearing force that separates the skin and superficial fascia from the deep fascia, creating a potential space where hemolymphatic fluid accumulates. These lesions are often misdiagnosed due to their variable clinical presentation and heterogeneous morphology, which can lead to confusion with conditions such as hematoma, fat necrosis, and sarcoma. The typical localization of the lesion is the trochanteric region. This case report presents the clinical and radiological findings, along with the diagnosis and treatment process, of a 56-year-old female patient who developed a Morel-Lavallée lesion in the prepatellar region following a fall. In the first stage, no bone abnormality was seen in computed tomography (CT) imaging. Magnetic resonance imaging (MRI) and ultrasonography (USG) performed as a result of her ongoing complaints revealed a well-defined fluid accumulation in the prepatellar region, consistent with a Morel Lavallée lesion. Clinical examination and patient history are essential for diagnosis. However, MRI and USG play an important role in confirming the diagnosis and monitoring the course of the disease. A classification has been proposed for Morel-Lavallée lesions, which are divided into six subtypes based on MRI features. USG is particularly practical and useful modality both for initial diagnosis and follow-up evaluation. Some lesions may resolve spontaneously. If not recognized and treated appropriately, they may become chronic or complicated, requiring more invasive interventions. Recognizing the lesion’s characteristics and implementing a personalized treatment strategy are essential for achieving optimal patient outcomes.