Epidemiological features of brain tumors in the first 3 years of life.

We investigated the age-related location, gender distribution, and histology of 75 brain tumors in children under 3 years of age seen in our department between 1984 and 1997. These were characterized by a higher overall incidence in boys (42/33 cases; ratio 1.3) and a prevalence for a supratentorial location (48/27 cases; ratio 1.7); the most common histological entities were astrocytoma (25.3%) and ependymoma (17.3%), followed by medulloblastoma (13.3%) and PNET (10.8%); 44% were high-grade tumors corresponding to WHO grades III and IV. In the 1st (22 cases), 2nd (25 cases) and 3rd (28 cases) years of life, the boy-girl ratios were 1.0, 1.5 and 1.3, respectively, while there was a decrease with age in the frequency of supratentorial (ratios 3.4, 1.1, and 1.2) and high-grade tumors (77.3%, 36.0%, and 32.1%). In the 1st year of life the most common neoplasms were PNETs (22.7%) and in the 2nd year both astrocytomas and ependymomas (24.0 % each); astrocytomas (35.7%) prevailed in the 3rd year of life.