Chondromyxoid fibromas of the neurocranium.

We report a case of a chondromyxoid fibroma involving the upper clivus in a 73-year-old man. Chondromyxoid fibromas are uncommon benign bone tumors that rarely involve the skull. Chondromyxoid fibromas arising in the membranous neurocranium resemble their extracranial counterparts, appearing as radiolucent lesions with sclerotic margins and presenting most often as a painless focal swelling. Chondromyxoid fibromas arising in the chondrocranium differ from their extracranial counterparts and from those arising in the membranous neurocranium. They appear as locally destructive, often calcified, and exophytic lesions without sclerotic margins and present with cranial nerve dysfunction and symptoms caused by central nervous system compression.