Pediatric brain tumours at a tertiary care hospital in Karachi.

The objectives of this study were to determine the epidemiology of brain tumors during infancy and childhood and to define and segregate childhood brain tumors vis-a-vis their morphological characteristics. The present study includes pediatric brain tumors, ICD-10 category C71 encountered during 10 years (January 1989 through December 1998) at a tertiary care hospital in Karachi. Eighty one cases were included, 58 (71.6%) in males and 23 (28.4%) in females with a male to female ratio of 2.5:1. The cases were divided into 3 age groups each covering five years of life (0-4, 5-9, 10-14 years), with the greatest number in the second age group i.e. 5-9 years followed by the third age group and the 0-4 year age group. The mean age for all cases, both genders was 8.8 years (95% CI 7.9; 9.6) with a marginal variation for cases occurring in the cerebrum and cerebellum. The malignancies occurred at a younger age in the males for each subcategory by site and morphology. The morphological distribution of cases was astrocytoma (28 cases, 34.6%), primitive neuroectodermal tumor or PNET (40 cases; 49.4%), ependymoma (8 cases, 10%), mixed glioma (4 cases; 5%) and a case of oligodendroglioma. The 81 malignancies included in this study were further categorized by site into two groups, supratentorial (27 cases; 33.3%) and infratentorial (54 cases; 66.7%). The morphological categorization of supratentorial tumors was astrocytoma (17 cases; 63%), ependymoma (5 cases; 18.5%), mixed glioma (2 cases; 7.4%). PNET with rhabdoid differentiation, oligodendroglioma and pinealoblastoma comprised 1 case (3.7%) each. The 17 supratentorial astrocytoma were sub-categorized as follows - pilocytic astrocytoma (5 cases; 29.4%), grade II astrocytoma (6 cases; 35.3%); grade III astrocytoma (2 cases; 11.8%), anaplastic astrocytoma (1 case; 5.9%) and glioblastoma multiforme (3 cases; 17.7%). The morphological categorization of infratentorial tumors was astrocytoma (11 cases; 20.4%), medulloblastoma (38 cases; 70.4%), ependymoma (3 cases; 5.6%) and mixed glioma - astroependymoma (2 cases, 3.7%). The morphological sub-categorization of infratentorial astrocytoma was pilocytic astrocytoma (7 cases, 63.6%), with gemistocytic astrocytoma, grade II, grade III and anaplastic astrocytoma comprising 1 (9.1%) case each. The morphological categorization of medulloblastoma was classical medulloblastoma (15 cases; 39.5%), desmoplastic medulloblastoma (8 cases; 21.1%), medulloblastoma with astrocytic differentiation (12 cases; 31.5%), medulloblastoma with neural differentiation (2 cases; 5.3%), and neuroblastic medulloblastoma (1 case; 2.6%). The pediatric brain tumors in Karachi reflect a developing country scenario, with a strong male predisposition and a late presentation with a peak in the 5-9 year age group. There is a predominance of medulloblastoma and a paucity of astrocytomas. The current study is a single institution study and needs cautious interpretation. Population-based studies are required to determine the cancer burden due to pediatric malignancies of the brain in this population and for the morphological categorization of brain tumors in Karachi.