A case of congenital ependymoblastoma

Abstract

We report a case of congenital ependymoblastoma. A female fetus was prenatally diagnosed as having a posterior fossa tumor and hydrocephalus on prenatal ultrasound study. She was born at 39 weeks of gestation with birth weight of 2846g. The head circumference was enlarged to 39.4cm. A miniature Ommaya's reservoir was inserted to control hydrocephalus on day 4 of life. Tumor biopsy was performed on day 11 and followed by chemotherapy. The histologic specimen showed dense cellularity with abundant ependymoblastemal rosettes and mitotic figures. Histopathological diagnosis of ependymoblastoma was made. On immunohistochemical studies, the rosettes showed strong positivity for vimentin. GFAP was positive in several rosettes. EMA was positive on the luminal surface of some rosettes. There was a small area in which cells were relatively sparse and this area showed neurofilament and synaptophysin positivity, which is unusual for ependymoblastoma.
Ependymoblastoma is classified as an embryonal tumor in the WHO classification of brain tumor 2000. It is presumed that ependymoblastoma arises from a primitive neuoroepithelial cell showing some phenotypic features of ependymoglia. Neural components are usually not seen in ependymoblastoma. Ependymoblastoma with neural differentiation has been reported previously as a rare entity. Although the abundance of ependymoblastemal rosettes could easily lead to a dignosis of ependymoblastoma, it seemed important to note the neural component when considering further characteristics and classification of this highly primitive tumor.