RESUMO
BACKGROUND: The Morel-Lavallée lesion is a post-traumatic collection of fluid arising after a 'closed degloving injury' has caused the separation of the skin and subcutis from the underlying muscular fascia. It usually occurs in the trochanteric region or proximal thigh. CASE DESCRIPTION: A 36-year-old obese man was referred to the emergency department by his general practitioner for fever and pain in the right lower abdominal quadrant. Blood testing revealed elevated infection parameters. As appendicitis was suspected, a CT scan of the abdomen was performed. This revealed a Morel-Lavallée lesion, which he had sustained 9 months earlier when he had been hit by a car while riding his bicycle. A rapid recovery ensued after ultrasound-guided percutaneous drainage and treatment with antibiotics. CONCLUSION: A Morel-Lavallée lesion, which could manifest even months later, should be considered after any traumatic injury. Ultrasound, CT and MRI are useful tools for proper diagnosis. There is no consensus about treatment in either the acute or the chronic phase to date.