Epidemiology of primary intracranial tumors in the Valle d'Aosta (Italy) during the 6-year period 1986-1991.

A total of 285 new cases of primary intracranial tumors (PIT: 178 cases, 62%) and secondary forms (107 cases, 38%) were detected by CT scan and MRI during a population-based study of the incidence rates of these neoplasms in the Aosta Valley (N.W. Italy: 114,325 residents in 1988) during the period 1986-1991. The PIT are discussed in this paper. Histological confirmation was obtained in 60%. Age- and sex-adjusted mean annual incidence rate for all PIT was 28.3/100,000 (men 21.7; women 28.1). The incidence rates by types were 9.7 for meningiomas (men 5.3; women 13.9), 9.1 for tumors of the neuroepithelial group (men 10; women 8.1), 3.7 for adenomas (men 2.6; women 4.6), and 1.9 for neurinomas (men 2.9; women 0.9). Incidence rate increased with age. Meningiomas comprised 37% of the PIT, followed by tumors of the neuroepithelial group (35%), adenomas (14%, neurinomas (7.3%) and malignant lymphomas (2.3%). The remaining subtypes were 4.6%. Our data showed a clearly higher incidence rate than in previous population-based surveys. The differences were most marked in the meningioma group. The extensive use of CT scan and the more intensive case-finding could explain the differences.