In the emergency department, we frequently manage patients with multiple contusions and bruise over the trunk without severe injuries. Emergency department discharge is a common option for these patients, and we may neglect the existence of closed internal degloving injury, which is a soft tissue injury with pelvic trauma, combining the subcutaneous tissue torn away from the underlying fascia followed by a cavity being filled with hematoma and liquefied fat created in the next few days (Harefuah 2006;145:111-3:66, J Trauma 1997;42:1046). We report the unusual occurrence of this entity in an 18-year-old man. He encountered a scooter accident and experienced a few days of hospitalization because of thoracispinal (T10 and T11) process fracture. He was discharged, but a fluctuating mass developed at the lumbar area 10 days later. The comprehensive survey excluded the cerebrospinal fluid leakage associated with spinal fracture, and internal degloving injury was diagnosed. Percutaneous drainage with compressive bondage was aggressively used. Even though the treatment course was time consuming, the lesion eventually disappeared 10 months after his first visit.