Case Report: An Unusual Case of Morel-Lavallée Lesion of the Upper Extremity
A 32-year-old woman presented for evaluation of upper arm pain and swelling after sustaining a work-related injury several days earlier.
Differential Diagnosis
The differential diagnosis includes compartment syndrome, coma blisters, a missed fracture, bullous pemphigoid, bullous drug reactions, and linear immunoglobulin A disease. Most of these conditions were easily ruled out in this case as the patient was previously healthy and not on any medications. The lesions in this case could have been confused with coma blisters, which are similar in appearance, self-limiting, and can develop on the extremities. However, coma blisters are classically associated with toxicity from various central nervous system depressants, as well as reduced consciousness from other causes—all of which were readily ruled-out based on the patient’s history. Moreover, the Morel-Lavallée lesion is a degloving injury of the subcutaneous tissue from the fascia underneath, whereas the pathology of coma blisters includes subepidermal bullae formation as well as immunoglobulin and complement deposition.6
Diagnostic Imaging
Morel-Lavallée lesion can often be confirmed via several imaging modalities, including ultrasound, CT, 3D CT, or magnetic resonance imaging (MRI).3,7 Ultrasound will usually show a well-circumscribed hypoechoic fluid collection with hyperechoic fat globules from the subcutaneous tissue, whereas CT tends to show an encapsulated mass with fluid collection underneath. In MRI, Morel-Lavallée lesion often appears as a hypointense T1-sequence and hyperintense T2-sequence similar to most other fluid collections. There may be variable T1- and T2-intensities with subcutaneous tissues in the fluid collection.2
Management
Despite recognition of this disease entity, controversies still exist regarding management. Case reports have demonstrated a relatively high rate of infected fluid collections depending on the chronicity of the injury.8 A recent algorithm to management described by Nickerson et al4 proposes that for patients with viable skin, percutaneous aspiration of more than 50 cc of fluid from these lesions should be treated with more extensive operative intervention based on the increased likelihood of recurrence. Patients without viable skin require formal debridement with possible skin grafting.
Other treatment options include conservative management, surgical drainage, sclerodesis, and extensive open surgery.8-10 Management is always case-based and dependent upon the size of the lesion and associated injuries.
Conclusion
This case represents an example of Morel-Lavallée lesions in their most severe and atypical form. It also serves as a reminder that vigilance and knowledge of this disease process is important in helping to diagnose this rare but potentially devastating condition. The key to recognizing this injury lies in keeping this disease process in the differential diagnosis of traumatic injuries with suspicious mechanism involving significant shear forces. Significant physical examination findings may not be present initially and evolve over a time period of hours to days. Once this injury is identified, management hinges on the size of the lesion and affected body part. Despite timely interventions, Morel-Lavallée lesions may result in significant morbidity and functional disability.
Dr Ye is an emergency medicine resident at the Brown Alpert Medical School in Providence, Rhode Island. Dr Rosenberg is a clinical assistant professor at Brown Alpert Medical School, and an emergency medicine attending physican at Rhode Island Hospital and The Miriam Hospital, Providence, Rhode Island.
