Myositis ossificans is usually the result of direct injury to a muscle and is a self-limiting disease. It may present as a soft-tissue mass with a broad differential diagnosis, including highly malignant tumours, such as soft-tissue sarcomas. Many theories can be found concerning the aetiology of myositis ossificans, but minor or major traumas are considered to be the most common cause. A unique case of myositis ossificans of the neck in a 17-year-old professional, female, ground gymnast, who presented initially with a soft-tissue tumour, was treated successfully. The main differential diagnosis is presented along with typical radiographic features on conventional radiography, computerised tomography and magnetic resonance imaging, and typical pathological appearance, such as the pathognomonic "zoning phenomenon". Myositis ossificans should be added to the differential diagnosis of every young patient who engages in sport presents with a soft-tissue mass. Careful padding of the area and teaching the rolling technique to avoid repeated injuries to the neck can prevent recurrence.