Pathology

Question 1

Classic medulloblastoma

Answer 1

Densely packed small rounded cells with mild to moderate nulclear pleomorphism and high mitotic count
Homer wright Rosettes : primitive tumor cells surrounding central neuropoli

Question 2

Homer wright Rosettes

Answer 2

Primitive tumor cells surrounding central neuropoli

Question 3

Most favorable subtype of medulloblastoma

Answer 3

WNT- Activated..Rarest subtype (10%) ..Nuclear B-catenin

Question 4

Hemangioblastoma

Answer 4

Sporadic
Or inherited von hippel-lindau disease (VHL)

Question 5

Morphological variants of medulloblastoma

Answer 5

Classic
Desmoplastic/ Nodular
Medulloblastoma with extensive Nodularity
Large ell / Anaplastic

Question 6

Gross picture of medulloblastoma

Answer 6

Most medulloblastomas Arise in Cerebellar vermis as (pink or grey friable mass ) that fill the 4th ventricle
Medulloblastomas located in the Cerebellar hemispheres tend to be firm and more circumscribed of desmoplastic/ Nodular variant
Small foci of necrosis can be seen but extensive necrosis is rare