The patient went on to have surgery. 

Histology

MICROSCOPIC FINDINGS

Section show a moderately cellular tumor comprising astrocytes showing hyperchromatic nuclei, moderate nuclear pleomorphism and ill-defined eosinophilic cytoplasm.  

Mitotic activity is not seen.  Rosenthal fibers or eosinophilic granular bodies are not identified.  There is no necrosis or microvascular proliferation. A Ki-67 stain shows a proliferative index of approximately 10%. 

Features consistent with a low-grade glioma and most in keeping with a protoplasmic astrocytoma.

Discussion

Until recently, protoplasmic astrocytomas were classified as a subtype low-grade astrocytoma, however, in the latest (2016) update to WHO classification of CNS tumors, protoplasmic astrocytomas no longer exists as a distinct entity. 

Note: IDH mutation status is not provided in this case and according to the current (2016) WHO classification of CNS tumors, this tumor would, therefore, be designated as a diffuse astrocytoma NOS.