A 30-year-old man with a 7-month history of mild sacral pain and intermittant left sciatica was found to have an expansile lesion in the sacrum on a plain radiograph. Biopsy confirmed a chondromyxoid fibroma which was removed surgically. A 1-year follow-up showed no recurrence. The case is the fifth to be reported. Plain film and MRI appearances, histology and treatment are described. The previously reported cases are reviewed and the current literature is discussed.