A 63-year-old man had low back pain and a huge protruding mass, larger than 10 cm in size, over the sacral region for 2 months. He also had progressive problems with leg strength, leg sensation, and urinary/fecal incontinence. Pelvic MRI was performed and demonstrated a large space-occupying lesion in the sacral region. F-18 FDG PET showed a large area of heterogeneously increased FDG uptake in the sacral region. Wide excision biopsy was performed and the cytology showed chordoma.