[Morel-Lavallee syndrome of the lower leg]

Morel-Lavallée syndrome, which appears after tangential trauma of highly vascularised tissues, is characterized by closed internal degloving injuries resulting in subcutaneous fluid collection. It can cause many complications. A 42-year-old man presented with open wounds after a violent right lower extremity trauma; the wounds were sutured. One month after the trauma, the patient complained of painful edema of the lower limb and fluid discharge from the previously sutured wounds. Local examination showed fluctuating fluid collection. Serum inflammatory markers were within the normal range. Ultrasound investigation of the right lower limb confirmed an extended fluid collection from the lower third of the thigh to the upper third of the leg, and CT scan delineated a surrounding capsule. The clinical and radiological data supported a diagnosis of post-traumatic Morel-Lavallée syndrome. Local surgical debridement and drainage associated with systemic antibiotic therapy (the fluid was found to be infected with oxacillin-resistant Staphylococcus epidermidis) resulted in rapid improvement.

Morel-Lavallée syndrome commonly appear after tangential trauma of highly vascularised tissues. The skin and the subcutaneous fat tissue are abruptly torn from the underlying muscle fascia, shearing the lymphatic vessels, rendering lymphostasis impossible. The local inflammatory reaction can cause the formation of a fibrous capsule resulting in a fluid collection. The clinical signs are not specific. When examining a soft-tissue collection or slow-healing wounds, the dermatologist should always rule out previous soft-tissue trauma; simple imaging studies will confirm the diagnosis if Morel-Lavallée injuries are suspected.

All dermatologists consulted by young patients without vascular disease for an unusual swelling and/or for slow-healing wounds should be mindful of this syndrome.