A Morel-Lavallée lesion of the proximal calf in a young trauma patient: A case report.

RATIONALE: The Morel-Lavallée lesion (MLL) is a closed degloving injury developing when shear force acts between the muscle fascia and the subcutaneous layer. MLLs develop principally in the trochanteric area or the pelvis; lesions in the proximal calf are rare. Acute lesions can be treated conservatively, but chronic lesions are best treated surgically because of a high rate of recurrence. To the best of our knowledge, this is a rare case of successful treatment of an MLL in the proximal calf associated with tibio-fibular shaft fracture. PATIENT CONCERNS: A 14-year-old male visited our emergency room after having been hit by a car. He exhibited direct trauma to the right lower leg and a distal tibio-fibular shaft fracture without an open wound. He underwent surgery to treat the fracture, which was immobilized with splint for 2 weeks post-operatively. At the 3-month follow-up, he complained of a painless, mobile, soft tissue mass in the posteromedial aspect of the proximal calf. Blood circulation was normal and we found no neurological abnormality in the distal region of the lower leg. DIAGNOSIS: A plain radiograph of the right lower leg revealed a proximal, round, radiopaque soft tissue lesion. Ultrasonography revealed a homogeneous, hypoechoic fluid collection. Magnetic resonance imaging revealed fluid of homogeneous signal intensity between the subcutaneous layer and the underlying fascia of the gastrocnemius muscle. INTERVENTIONS: Percutaneous drainage and intralesional steroid injection were performed on several occasions, but the lesion recurred every time. After 5 aspirations, we scheduled surgery. We radically excised the mass and sutured the superficial to the deep fascia to prevent shearing at the surgical plane. OUTCOMES: No complication or recurrence was noted at the 1-year follow-up. LESSON: An MLL in the proximal calf is an uncommon post-traumatic lesion and care must be taken to avoid misdiagnosis. If an MLL is suspected after imaging studies and physical examination, it is important to determine whether the lesion is acute or chronic and to plan treatment accordingly. Appropriate treatment should be given to patients to improve outcomes.