MR imaging characteristics of Morel-Lavallee lesions in pediatric patients

Abstract

Aim: Morel-Lavallée syndrome (MLS) is a serious posttraumatic soft tissue injury in which the subcutaneous tissues are separated from the underlying fascia by glove-finger (closed type) peeling and replaced by a cavity filled with hematoma and fat. It is most commonly seen in the trochanter major, but it can also be found in the flank, hip, and lumbodorsal regions. The goal of this study is to define the typical findings of MLS in order to avoid misdiagnosis and delay in patient treatment. Material and Method: This retrospective study was approved by the Institutional Review Board. Informed consent was waived due to the retrospective nature of the study. Between 2015 and 2021, MR images and clinical follow-ups of 22 pediatric patients with clinical and radiological Morel-Lavallée lesions (MLL) were reviewed retrospectively. All patients were evaluated using 1.5T or 3T power MR devices (Siemens Healthineers, Erlangen, Germany). Results: Of 22 patients diagnosed with MLS, 77% (n=17) were male and 23% (n=5) were female. Patients ranged in age from 7 to 18 years, with a mean of 13.2 years (+/-2,3). The locations of MLL were knee (77%, n=17, 15 patients had anterior knee and 2 patients had posterior knee involvement), hip (14%, n=3) and thigh (9%, n=2) in order of frequency. These lesions all had a similar ovoid shape. The majority of patients (18/22) received solely conservative management but three patients underwent percutaneous drainage. Conclusion: In our study, the importance of differential diagnosis of MLL from traumatic collections and the importance of MRI findings in diagnosis and treatment were discussed. Accurate diagnosis and treatment of MLL are critical, as the lesion's size may increase as a result of delayed treatment, causing skin necrosis and denervation due to the mass effect.