A 15-year-old boy underwent radiation therapy for a pineal tumor. He appeared to enjoy complete clinical recovery, follow-up computed tomography (CT) scans showed no evidence of residual tumor. Surgery was not performed. The tentative diagnosis of pineal germinoma was based on the tumor response to radiation therapy. However, 5 years later, the patient visited the hospital with a complaint of left knee pain. Myelography disclosed scattered spinal tumors below the Th₁₂ level, and laminectomy and biopsy showed the tumors to be pineoblastoma. Thus, it is likely that the initial pineal tumor was not germinoma but pineoblastoma and, in fact, on re-evaluation of the earlier CT scan, the characteristic features of pineoblastoma were evident. It has been well accepted among neurosurgeons that, for pineal tumors, radiation therapy is the treatment of first choice, unless the neuroradiological findings suggest a radiation-resistant tumor, such as teratoma. Both pineal germinoma and primitive neuroectodermal tumor (medulloblastoma, neuroblastoma, and pineoblastoma) are sensitive to radiation therapy. On the other hand, it is well known that, whereas pineal germinoma is relatively benign, pineoblastoma is not. It may be advisable for neurosurgeons to adopt a more aggressive approach to pineal tumors, including biopsy and histological diagnosis prior to treatment planning.