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45-Year-Old Woman with Left Neck Pain
This case features a 45-year-old woman presenting with left neck pain, ultimately diagnosed with a chondrosarcoma of the skull base.
Imaging overview:
Axial bone CT demonstrates a destructive mass centered at the petro-occipital suture with lateral central skull base osseous erosion and internal chondroid matrix mineralization in a ring and arc pattern, reflecting endochondral ossification. Axial T2 fat-saturated MRI shows markedly bright T2 signal intensity characteristic of cartilaginous tumors. Axial ADC mapping demonstrates very high signal intensity, consistent with the high water content of chondroid matrix.
Clinical insight:
Chondrosarcomas are malignant cartilaginous tumors, with 6 to 7% occurring in the head and neck. At the skull base, they characteristically arise at the petro-occipital suture, a site of endochondral ossification, distinguishing them from chordomas which arise at the midline clivus. The ring and arc pattern of calcification on CT reflects the chondroid matrix and is a key diagnostic feature. Markedly high T2 signal and elevated ADC values reflect the high water content of the myxoid cartilaginous matrix. CT best demonstrates the osseous destruction and matrix mineralization, while MRI characterizes soft tissue extent and helps differentiate chondrosarcoma from other skull base lesions.
Case courtesy of Madison Gardner and Rick Wiggins, MD, University of Utah Health.