Biological Behavior of the Primitive Neuroectodermal Tumor

Abstract

The authors analyzed 10 cases of primitive neuroectodermal tumors, excluding medulloblastoma, pineoblastoma, ependymoblastoma and central neuroblastoma, operated from January 1980 to March 1988. These tumors comprised 5.8'1c, (9/156) of total pediatric (age< 16) brain tumors in the authors' series. Of the 10 cases, symptoms of increased intracranial pressure were noted in 9 cases, focal neurological deficits in 5 cases. One case showed seizures only. Computerized tomography findings were characteristic. A large mass of mixed density containing cystic areas with strong enhancement of the solid portion suggested this tumor. In all of the 6 cases, who had surgical removals with or without the irradiation of the brain, the tumor recurred and 4 of them showed seeding along the pathway of the cerebrospinal fluid (CSF) in spite of the radical removal of the tumor in 2 of the cases. On the other hand, 2 cases, who had surgical removal and whole neuraxis irradiation, with or without chemotherapy, remained disease free 18 and 4 months after surgery. Although the experiences are limited, the whole neuraxis irradiation is considered to be mandatory for the prevention of the seeding along the CSF pathway. And the authors experienced an encouraging result of the management of this malignant tumor with more aggressive treatment modalities.