Biphasic astroglial tumor with low to moderate cellularity of alternating loose and cellular areas. The loose areas are formed of multipolar cells with microcyst formation. The dense areas are formed of bipolar cells with elongated eosinophilic processes (Rosenthal fibers). Tumor shows many capillary and branching blood vessels but no evidence of endothelial proliferation. No evidence of tumor necrosis. No evidence of anaplasia or mitosis. Picture is consistent with pilocytic astrocytoma which is a WHO grade I tumor. Marker study (GFAP, Olig-2, IDH-1, p53 and Ki-67) is recommended for confirmation and further characterization.
Brain tumor.
Soft tissue fragments collectively measured 3x2.5x0.7 cm, totally embedded.
Brain tumor, excision: