Musculoskeletal images. C3 aneurysmal bone cyst.

neck pain for several months. Radiography revealed a mass in the posterior aspect of the left side of the neck. Open biopsy after computed tomography revealed an aneurysmal bone cyst. Examination by a team comprising general, orthopedic and spinal surgeons with an interest in surgical oncology, found a full range of motion in the cervical spine. Muscle bulk was symmetrically distributed and tone was normal. Formal motor testing revealed grade 5/5 strength in all muscle groups of both arms and legs. The deep tendon reflexes were symmetrically 2/4, and the patient was neurologically intact to light touch. Coordination and gait were normal. Magnetic resonance imaging demonstrated a multilobulated enhancing mass involving the left side of the vertebral body of C3, extending posteriorly through the pedicle and infiltrating the C2–3 facet joint as well as the lamina and spinous processes bilaterally at C2 and C3 (Fig. 1). Computed tomography detailed the erosive nature of the tumour (Fig. 2). Along its course the tumour also encased the left verteSurgical Images Imagier chirurgical