Secondary anaplastic oligodendroglioma after cranial irradiation: a case report.

Secondary brain tumors rarely arise after cranial irradiation; among them, meningiomas and glioblastomas are the most common and secondary oligodendroglial tumors the most rare. We present a 48-year-old man who developed an oligodendroglial tumor 38 years after receiving 50 Gy of cranial irradiation to a pineal tumor. He underwent gross total removal of a calcified, ring-enhanced mass in the right temporal lobe. The tumor was histologically diagnosed as anaplastic oligodendroglioma. Our review of previously reported secondary oligodendroglial tumors that developed after cranial irradiation revealed that these rare tumors arose after low-dose cranial irradiation or at the margin of a field irradiated with a high dose. We suggest that secondary oligodendroglial tumors arising after cranial irradiation are more aggressive than primary oligodendrogliomas.