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.
Hypercellular smear composed of cohesive and dispersed bipolar piloid astrocytic cells with elongated hair-like processes in a fibrillary background.
Well defined lobulated complex cystic solid mass lesion in the posterior fossa predominantly involving cerebellar vermis and right cerebellar hemisphere posteriorly with multiloculation and septation.
Two samples were received:
1- Soft tissue fragments collectively measured 5.8x5.5x1.5 cm, larget measuring 3x2x1.5 cm.
2- Two ml pale yellow fluid, one smear was prepared and pap stained.
Posterior fossa mass, excision: