Secular trends of cerebellar gliomas in children.

Temporal changes in the histologic composition of cerebellar gliomas were examined in a population of 132 children operated on between 1927 and 1968 at The Children's Hospital Medical Center of Boston. Linear trends with time were examined for clinical features, histologic features, and tumor types. We found evidence of an increasing occurrence of glioma A and its associated features during the 41-year study period. This tumor type is associated with a good prognosis and is histologically well defined. Glioma B, a tumor type associated with a poor prognosis, was relatively stable with respect to time and, therefore, differed markedly from glioma A. Foci of oligodendroglia, a glioma A feature, clustered by year of surgery within a relatively short time span. This feature had a survival rate and a male sex proportion quite different from those of the other histologic features investigated.