Giant cell tumour with a lipoma of the sacrum

We report the case of a 58-year old female who presented with insidious low back pain radiating to the buttock and thigh. Magnetic resonance imaging revealed a heterogenous high-signal (on T2-weighting) in the midline of the sacrum. Within this mass was a distinct area of low-signal intensity. Computed tomography revealed a lytic lesion within the sacrum. Biopsy confirmed the presence of a lipoma that contained within it a giant cell tumour. The patient proceeded to have surgical excision and bone graft augmentation.