Primary leptomeningeal ependymoblastoma. Case report

Area of Science:

• Neuro-oncology
• Pathology

Background:

• Ependymoblastoma is a rare, primitive malignant glioma with ependymal differentiation, typically affecting very young children.
• Characterized by rapid growth and diffuse leptomeningeal infiltration, it presents with immature cells and ependymal rosettes.

Observation:

• A case of ependymoblastoma in a 17-year-old girl with diffuse leptomeningeal spread was analyzed.
• No primary site within the neuraxis was identified despite thorough examination.
• Histological analysis suggested origin from a heterotopic glial nest in the subarachnoid space.

Findings:

• Immunohistochemical markers for neural and glial differentiation (GFAP, S-100, NSE, neurofilaments) were negative.
• This absence of differentiation markers complicated definitive tumor classification.
• The tumor predominantly infiltrated the leptomeningeal space.

Implications:

• This report describes the first known case of primary leptomeningeal ependymoblastoma.
• The findings suggest that ependymoblastoma may arise from ectopic glial rests outside the typical central nervous system origins.
• This case expands the understanding of ependymoblastoma's potential locations and origins, particularly in older patients.