Histologic features and observational variation in cerebellar gliomas in children.

Variation existed in the recognition of histologic features commonly used in the evaluation of cerebellar gliomas of childhood. Some histologic features (e.g., perivascular pseudorosettes, leptomeningeal deposits, and calcification) were more reliably observed than were others (e.g., Rosenthal fibers, cell density, and hypervascularity). Knowledge of which features tend to have greater observational variation may lead to improved definitions, less reliance of these features in clinical decisions, further studies of the potential sources of the variation, and guidelines for minimizing observational variation.