Infratentorial

Question 1

Infratentorial masses DDx (7)

Answer 1

Atypical teratoma/rhabdoid.
Juvenile pilocytic astrocytoma.
Diffuse brain stem glioma.
Ganglioma
Medulloblastoma
Ependymoma
Haemangioblastoma

Question 2

Atypical teratoma/Rhabdoid (4)

Answer 2

Highly malignant tumours, rarely occur in patients older than 6.
Average age is 2 years, can occur before 1.
Can occur in supra and infratentorial locations, most commonly in cerebellum.
Large, angry looking tumours with necrosis and heterogenous enhancement.

Question 3

Juvenile Pilocystic Astrocytoma (3)

Answer 3

Cyst with a nodule in a kid.
WHO grade 1 but still enhance.
Located in posterior fossa or optic chiasm

Question 4

Diffuse brain stem glioma (4)

Answer 4

Seen in kids age 3-10, most commonly in the pons, which is usually a high grade fibrillary glioma.
T2 bright with subtle or no enhancement.
4th ventricle is flattened.
Imaging features are classic, biopsy not needed.

Question 5

Ganglioganglioma

Answer 5

Can occur at any age, anwhere and look like anything.

Question 6

Haemangioblastoma (4)

Answer 6

Cyst with a nodule in an adult.
Associated with VHL, especially if multiple.
Slow growing, indolent vascular tumours that can cause hydrocephalus from mass effect.
90% found in the cerebellum.