Epidemiological study of primary intracranial tumors in childhood. A population-based survey in Kumamoto Prefecture, Japan.

Between 1989 and 1995, we diagnosed primary intracranial neoplasms in 79 children younger than 15 years. All of them belonged to a well-defined population residing in Kumamoto Prefecture, Japan. Of the tumors, 64 (81.0%) were confirmed microscopically. The age-adjusted annual incidence rate was 34.3 cases per million child population. There was a marked difference in the incidence rate between boys (47.1) and girls (22.05). The age-specific annual incidence per million was 24.3 cases for the 0- to 4-year age group, 46.7 for the 4- to 9-year age group and 30.8 for the 10- to 14-year age group. The highest incidence rate was seen in 5- to 14-year-old boys (53.5), the lowest in 10- to 14-year-old girls (7.1). The most common tumors were astrocytomas (41.8%), with an incidence of 14.52 per million, followed by germ cell tumors (15.1%), with an incidence of 6.24 per million, craniopharyngiomas (15.1%), incidence 5.25 per million, ependymomas (6.3%), incidence 2.19 per million, and medulloblastomas (6.2%), incidence 2.19 per million. The distribution of tumor types varied with patient age at the time of diagnosis. Although no germ cell tumors were encountered in the 0- to 4-year age group, in the 10- to 14-year age group, they comprised about one third of all tumors. In contrast, white craniopharyngiomas were rare in the 10- to 14-year age group, they made up more than 22% in the 0- to 4-year age group. In this survey of Japanese children, we found a higher incidence of primary intracranial tumors, especially germ cell tumors and craniopharyngiomas, and a lower incidence of medulloblastomas compared to the incidence reported for Western countries.