Close
Sections show a moderately cellular tumour with a fibrillary background forming prominent perivascular pseudorosettes and focal ependymal canals. No true ependymal rosettes are seen. Tumour cells demonstrate mildly enlarged elongated nuclei and small nucleoli. No mitoses, necrosis or microvascular proliferation are seen. Immunohistochemically tumour cells stain:
- GFAP positive
- ATRX positive
- IDH1 negative
- p53 negative
- EMA negative
- Ki67 proliferation index is approximately 5%.
FINAL DIAGNOSIS: posterior fossa ependymoma (WHO Grade 2)
Slide images courtesy of the RMH Pathology Department.