RESUMO
BACKGROUND: The natural history of cerebral venous malformations has not been well documented, and the clinical significance of these common lesions remains controversial. OBJECTIVE: The objective of this study was to follow longitudinally the clinical course of patients with cerebral venous malformations to document the natural history of the lesion. METHODS: Ninety-two patients with radiographically confirmed venous malformations were entered into the study between 1987 and 1996. Annual follow-up was maintained by clinic visits and/or phone interviews. Sixty-three patients (25 men and 38 women) with more than 1 year of follow-up were analyzed. McNemar's test and logistic regression analysis was applied to prevalence of presenting symptoms over time. An average per patient follow-up of 4.2 years yielded 2,721 retrospective and 301 prospective lesion-years for analysis. RESULTS: Average age at diagnosis was 39.1 years (SD, 18.7 years; range, 2 to 73 years). The most frequent lesion locations included the frontal lobe (55.6%, n=35) and the cerebellum (27%, n=17). The most frequent presentations included headache (50.8%, n=32), focal neurologic deficits (39.7%, n=25), and seizure (30.2%, n=19). Prevalence of headache (p=0.048) and seizure (p=0.016) decreased over time without treatment of the lesion. A second cerebrovascular lesion was identified in 12 patients (19%). Two patients had a symptomatic intracerebral hemorrhage attributable to their venous malformation. Risk of hemorrhage was 0.15% per lesion-year (95% CI, 0.06 to 0.38%). CONCLUSIONS: This study establishes that the natural history of venous malformations is benign, that the risk of hemorrhage from these lesions is negligible, and that conservative therapy is warranted.