Retrosacral Morel-Lavallée Lesion: Resolution with Ultrasound-guided Drainage and Sclerotherapy

Morel-Lavallée lesions are chronic seromas due to closed degloving injuries, resulting from blunt trauma. They most commonly occur over the greater trochanteric, gluteal and flank regions. We present a case of retrosacral Morel-Lavallée lesion. Initial ultrasound demonstrated a fluid collection lying between the subcutaneous fat and the underlying fascia superficial to the sacrum. Following repeated ultrasound-guided aspirations, further recurrence of a superficial pre-sacral seroma was confirmed with MRI. Ultrasound-guided aspiration was performed and 100 mg of injectable doxycycline was instilled into the lesion. 4 months after sclerotherapy, the patient was asymptomatic, and follow-up MRI demonstrated no residual fluid collection or complication. This case demonstrates the value of using MRI in conjunction with ultrasound to characterize Morel-Lavallée lesions in an atypical site and in confirming response to treatment, in addition to the use of sclerotherapy for treatment of a lesion refractory to repeated aspiration.