Clivus Fibrosis: Natural History of a Benign Condition Mimicking Chordoma

Introduction: Clivus fibrosis is a poorly described condition. On imaging it can mimic chordoma or fibrous dysplasia. The goal of this study was to describe the clinicopathological features of this entity and its natural history.

Methods: Between 2001 and 2004, five patients (three men, two women; mean age, 52.6 yrs; range, 31 to 64 yrs) were identified from our pathology database to have biopsy-proven clivus fibrosis. These patients' data were reviewed retrospectively.

Results: In all patients, the lesion was diagnosed incidentally on CT or MRI of the head obtained for unrelated symptoms (epistaxis, headache, tinnitus, sinusitis). Two patients had a history of disseminated coccidiosis and pulmonary tuberculosis, respectively. Two patients had a prior diagnosis of Charcot-Marie-Tooth disease and neurofibromatosis I, respectively. In all cases, the lesion was biopsied because it was thought to be a potential chordoma. Once pathological analysis confirmed clivus fibrosis, no resection was pursued. The patients' preoperative symptoms were unchanged after biopsy. All patients were followed for a mean of 49 months (range, 25 to 70 mos). None of the lesions progressed radiographically or clinically.

Conclusions: Clivus fibrosis is a benign condition that can mimic chordoma. The clival abnormality may be discovered incidentally on CT or MRI of the head performed for unrelated symptoms. A biopsy should be performed to rule out chordoma because the two conditions cannot be reliably differentiated from each other based on imaging alone.