MRI - MRI pelvis
What is the most common primary sacral tumour?
Chordoma is the most common primary sacral tumour, followed by giant cell tumour and chondrosarcoma.
What is the most common location for a chordoma?
Sacral involvement (30-50%), spheno-occipital chordoma (30-35%), vertebral body (15-30%).
Midline, grossly expansile, sacral mass that involves sacral segments S2-S5. There is no transarticular extension into the sacroiliac articulations. It demonstrates heterogeneous high signal intensity on STIR sequences and homogeneous low signal intensity on T1 sequences compared to normal bone marrow. There is effacement of the presacral soft tissues but with no evidence of frank soft tissue invasion.