Background
CNS tumors are the leading cause of cancer related deaths among children and adolescents. Nonetheless, the incidence of pediatric CNS tumors in developing countries is poorly understood. We aimed to provide epidemiologic features of primary malignant CNS tumors in Iranian children 0–19 years of age using National Cancer Registry (NCR) data bank.

Methods
The data recorded by NCR over a 10 year period (2000–2010) were reviewed.

Results
Of 1948 tumor cases, 93.3% were located in brain, 5.1% were found in the spinal cord & cauda equina, and 1.6% affected cranial nerves and other parts of the nervous system. The overall average annual age specific incidence rate was 1.43 per 100,000. Males were more likely to develop CNS tumors (1.65 per 100,000) compared to females (1.21 per 100,000, p < 0.01). Children under 5 years of age had the highest age specific incidence rate (1.86 per 100,000). Astrocytic tumors with the incidence rate of 0.61 per 100,000 were the most frequent specific histology followed by embryonal (0.38 per 100,000), and ependymal tumors (0.10 per 100,000). With regard to the histological distribution of tumors, some unique features including the high proportion of unspecified malignant neoplasms (7.6%) were noted.

Conclusion
The overall incidence rate was markedly lower than western findings. Major differences were also observed in incidence rates of specific histologies. Although the discrepancies may be attributable to diversity in classification schemes and registration practices, a real ethnic and geographical variation in predisposition to development of pediatric CNS cancers is strongly suggested.