Persistence and late malignant transformation of childhood cerebellar astrocytoma. Case report.

A 5-year-old girl with juvenile pilocytic astrocytoma subsequently had multiple episodes of symptomatic recurrence over the course of 21 years of follow-up review. This lesion underwent histological transformation to an anaplastic small-cell neoplasm 21 years after the initial resection and diagnosis. Late transformation of benign childhood cerebellar astrocytomas to malignant astrocytic tumors is very rare; transformation to an anaplastic small-cell neoplasm has not been reported previously. This case and other reported cases in which juvenile pilocytic astrocytoma recurred after a long interval indicate the requirement of long-term follow-up review of these patients before assuming either a cure or arrest of the tumor's growth.