Parasagittal meningiomas are either treated with conservative surgery or aggressive surgery with extensive vascular reconstructions to achieve radicality. The optimal management is subject to controversy. A prerequisite for good management and for design of relevant studies is the knowledge of natural history after radical and subtotal surgery.

All patients operated for parasagittal meningiomas at Karolinska Hospital between 1975 and 1979 were identified. This cohort of 51 patients was retrospectively analyzed to obtain 25-year follow-up data. Data were obtained from medical charts at all treating hospitals, the Swedish cancer registry, and the Swedish registry of causes of death. Radiology reports and images were reviewed. All patients still alive were contacted for visits, interviews, and radiologic imaging when indicated. Karnofsky index, Simpson grade, and pathologic examinations were obtained.

The total recurrence rate after 25 years was 47%. Ten- and 25-year recurrence rates for radically operated parasagittal meningioma (Simpson grade 1-2) were 13% and 38%, respectively. The recurrence rates increased with increasing Simpson grades; 10- and 25-year recurrence rates in the Simpson grade 4 group were 62% and 69%, respectively. The relative risk for recurrence in Simpson grade 4 patients was 1.78 compared to Simpson grade 1-3 patients. The 10- and 25-year mortality rates were 33% and 63%, respectively. Of the total mortality 50% was caused by the tumor after 10 years and 48% after 25 years.

A 25-year follow-up was necessary to estimate the long-term outcomes of parasagittal meningiomas. It is necessary to consider long-term recurrences and morbidity as important factors when managing patients with parasagittal meningiomas whose life expectancies are not diminished by old age or co-morbidities. The long-term outcomes must also be considered when evaluating different treatment modes, as "cure" of parasagittal meningiomas cannot be evaluated without sufficient follow-up.