Natural history of petroclival meningiomas

Introduction: This last decade there has been a marked evolution in microsurgical management of petroclival meningiomas. In some cases though radical resection is incompatible with good postoperative quality of live. Focusing on conservatively treated patients the purpose of this study was to determine some guidelines about how far and at which location aggressive surgery is indicated. Methods: In a cooperative study of 98 patients with petroclival meningioma, involving both neurosurgical departments (1, 2) 21 patients (21%) were treated merely conservatively because of different reasons. We evaluated the clinical and functional status as well as the radiological findings of these patients from the time of diagnosis up to a minimal follow-up of 4 years. We made an analysis of the outcome and quality of live in correlation with the radiological findings and evolution. Results: Nine patients (33%) presented with cranial nerve deficit, 4 (19%) with impaired functional status. Radiological tumor size was small (<2 cm) in 7 (33%), medium (2-3 cm) in 9 (42%), large (3-4.5 cm) in 4 (19%) and giant (>4.5 cm) in 1 (4%). After a mean follow-up of 6.8 years further tumor growth occurred in 14 cases (67%) but with marked differences in velocity. Correlative functional deterioration was seen in 8 patients (38%). Two patients (9%) died because of the tumor. Infratentorial tumor growth at the clivus and CP-angle and tumor volume was significantly associated with functional impairment. These data were put into comparison with operatively treated tumors. Conclusions: Although histologically identical, different types (fast vs slow growing, infiltrating vs non-infiltrating) of petroclival meningiomas seem to occur. Radical resection in experienced hands is the optimal treatment but in some cases partial resection targeted on the infratentorial part must be accepted to preserve a good quality of live.