A 16-year-old boy from juvenile hall presented to the Emergency Department complaining of a right scalp “bump” for approximately 2 months. The “bump” was not painful but, on occasion, felt “sore.” It apparently started after he was kicked in the head in the same area during a fight 2 months prior. He reported no loss of consciousness, headache, neck or facial pain, hearing or vision changes, or balance or gait abnormalities. Review of systems was otherwise negative. The patient’s past medical and surgical histories were unremarkable. He admitted to occasional alcohol and marijuana use. He denied a family history of bleeding disorders, strokes, or chronic diseases. He took no prescription or over-thecounter medications. On physical examination, the patient was a welldeveloped 16-year-old boy, able to walk around the examination room comfortably with normal balance and gait. He stepped up and sat on the table without difficulty. The head, ears, eyes, nose and throat examination (HEENT) was significant for a 3–4 cm 1 cm right posterolateral scalp mass with a palpable thrill. The mass was soft, pulsatile, mobile, non-tender, and had no overlying skin changes. His HEENT examination was otherwise unremarkable, as was the remainder of his physical examination. The patient had normal coagulation studies and complete blood count. With a preliminary diagnosis of scalp