Morel-Lavallée Injuries: A Multimodality Approach to Imaging Characteristics.

Morel-Lavallée lesions are relatively rare closed degloving injuries caused by a shearing force resulting in separation of the dermis and the hypodermis from the subjacent deeper fascia. Although most commonly encountered lateral to the greater trochanter, these injuries may occur throughout the body in a variety of locations. Separation of the hypodermal tissue planes results in a complex serosanguinous fluid collection with areas of internal fat necrosis. The imaging appearance is variable and nonspecific, potentially mimicking superficial hemorrhagic bursitis, or cystic or necrotic primary soft tissue neoplasms. If not treated in the acute or early subacute setting, these collections are at risk of superinfection, overlying tissue necrosis, and continued expansion. In this article, we will review the pathophysiology, cross-sectional imaging features, and differential diagnostic considerations of Morel-Lavallée lesions as well as discuss management and treatment options.