Presentation
Pregnant lady with increasing headaches.
Patient Data
There is a 4 cm T2 hyperintense midline cerebellar mass which distorts the fourth ventricle and medulla without significant hydrocephalus but resulting in crowding of foramen magnum with mild cerebellar tonsillar herniation.
Case Discussion
The patient went on to have a resection.
Histology
Sections show a variably cellular tumor with a prominent microcystic architecture. Tumor cells
demonstrate elongated oval nuclei with inconspicuous nucleoli set within a fibrillary stroma. Frequent Rosenthal fibers and eosinophilic granular bodies are seen. There are focal aggregates of thin-walled, hyalinised blood vessels with the adjacent parenchyma containing hemosiderin deposition. No mitoses, necrosis or microvascular proliferation are identified.
IMMUNOHISTOCHEMISTRY RESULTS:
- GFAP: Positive
- IDH-l R132H: Negative (non-mutated)
- ATRX: Positive (non-mutated)
- p53: Positive
- BRAF V60oE: Negative
- Topoisomerase labeling index: Approximately 1-2%.
FINAL DIAGNOSIS: Pilocytic astrocytoma (WHO Grade I).
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