Chondrosarcoma of Petrous Apex

This axial T2-weighted MR image shows a high signal lesion in the petrous apex region, also involving the clivus. The lesion is expansile and there is evidence of bone destruction. Histopathology demonstrated chondrosarcoma.

Chondrosarcomas of the skull base are typically off-midline, destructive lesions with high T2 signal and strong but heterogeneous contrast-enhancement. Approximately 50% demonstrate chondroid matrix calcification (best seen on CT).

Skull base chondrosarcoma has a better prognosis than skull base chordoma, with an 80% 5-year progression-free survival after resection and radiotherapy.

References:
1. Osborn A. Diagnostic Neuroradiology Mosby 1994
2. Cho YH, et al. Chordomas and chondrosarcomas of the skull base: comparative analysis of clinical results in 30 patients. Neurosurg Rev 2008;31(1):35-43

Credit: Dr Laughlin Dawes