The Sound of Hoofbeats (abstract)

The procedure was a biopsy of the whitish material in the vitreous. The hypercellular vitreous sample demonstrated an astrocytic neoplasm within a necrotic background, consisting of small-to-medium sized cells with scant cytoplasm and oval, pleomorphic, hyperchromatic nuclei. Immunohistochemistry showed diffuse cytoplasmic glial fibrillary acid protein (GFAP) and nuclear oligodendrocyte transcription factor (Olig2) expression. The Ki67 proliferation labeling index was approximately 10%, and a subset of cells were also positive for mutant IDH-1 protein, revealed strong positivity for p53, and exhibited loss of ATRX. The histological and immunohistochemical findings were identical with those of the brain tumor. Cerebral high grade astrocytomas typically harbor poor outcomes as their invasive nature makes resection difficult and their resistance to chemoradiation usually leads to local recurrence. Furthermore, our patient's glioblastoma exhibited expression of the mutant IDH-1 protein, which has been shown to correlate with increased tumor size, presence of satellite lesions, and evidence of diffuse spread on MRI.