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.