The blade of grass sign, also called the candle flame sign, refers to the lucent leading edge in a long bone seen during the lytic phase of Paget disease of bone.
The blade of grass sign is characteristic of Paget disease of bone. This is akin to osteoporosis circumscripta cranii seen in the skull. A potential pitfall is misdiagnosing the track sign of the femur as the blade of grass sign.
Other Paget disease-related signs: