Prepatellar Morel-Lavallée Effusion Mimicking a Bursitis.

Morel-Lavallée lesions are traumatic abnormalities characterized by the accumulation of hemolymphatic fluid collection following disruption of subcutaneous fat tissue from the underlying deep fascia. Here, we present the case of a 63-year-old woman with a prepatellar Morel-Lavallée lesion, an unusual location for this pathology initially misdiagnosed as prepatellar bursitis. An MRI was performed allowing the correction of the diagnosis, highlighting the essential role of imaging in confirming the diagnosis and ruling out differentials such as prepatellar bursitis or neoplastic origins. In our case, conservative treatment with compression alone was employed, since surgery is reserved for chronic or complicated cases. Our experience underscores the utility of MRI in accurately delineating the anatomical extent and characteristics of prepatellar Morel-Lavallée effusion (PMLE). This imaging modality serves as a critical tool in guiding appropriate management strategies, ensuring timely and effective treatment for patients presenting with this lesion.