Recurrence of infantile supratentorial ependymoma after 23-year remission following surgical removal and radiation therapy.

We report on a patient with ependymoma who had a recurrence after long-term remission. The patient developed frontoparietal ependymoma at the age of one year and ten months. The tumor was radically removed and postoperative radiation therapy was performed. A calcified area adjacent to the area of surgical removal remained unchanged until the patient was 18 years old. The patient was healthy except for mild hemiparesis until an MRI scan performed when he was 25 years old showed regrowth of the tumor. The patient underwent surgery with additional radiation therapy and was discharged. The 23-year interval until tumor recurrence in this case is far beyond the so-called risk period of "Collins' law". Immunohistochemical study with MIB-1 and anti-p53 antibody showed a high proliferative potential of the primary and recurrent tumors and possible p53 mutation in the primary tumor. This is the first report to describe the detailed clinical course and histological features of a recurrent infantile ependymoma that progressed after Collins' risk period. It seems that follow-up of ependymoma patients after initial treatment should be performed regularly for a longer period in cases showing radiological evidence of a residual lesion.