Intraventricular

Question 1

Interventricular (2)

Answer 1

Tumours can arise from ventricular wall, septum pellucidum or choroid plexis.

Question 2

Ventricular wall and septum pellucidum origin DDx (6)

Answer 2

Ependymoma (kids)
Medulloblastoma (kids)
SEGA (Subependymal Giant Cell Astrocytoma) (kids)
Subependymoma (adult)
Central neurocytoma (young adult)

Question 3

Ependymoma (7)

Answer 3

Bimodal age distribution, large peak around 6YO, smaller peak at 30.
2 kinds:
4th ventricle
- 70%
- frequent extension into the foramen of Luschka and Magendie.
- “Plastic tumour” or “toothpaste tumour” because they squeeze out of the 4th ventricle
Parenchymal supratentorial (30%)
- Usually big (>4cm) at presentation

Question 4

Medulloblastoma (7)

Answer 4

Classic medulloblastoma, type of PNET.
Paediatric tumour occuring mostly before age 10 (second smaller peak 20-40).
Arise from cerebellar vermis, projecting into the 4th ventricle. Met via CSF pathways.
Heterogenous on T1 and T2, with homogenous enhancement.
Much more common than ependymomas.
They’re hypercellular and restrict diffusion.
Calcify 20%, less than ependymomas.
Like to “drop met” into CSF.
“Zuckerguss” - sugar icing as seen on post contrast imaging of the brain and cord.
Associated with basal cell naevus syndrome and Turcots syndrome

Question 5

Gorlin syndrome (6)

Answer 5

Medulloblastoma with dural calcifications.
They also get skin BCCs after radiation and have odontogenic cysts.
Pre-op imaging of the entire spinal axis should be done with posterior fossa neoplasm, especially if meduloblastoma or ependymoma.
Evidence of tumour spread is a predictor of outcome

Question 6

Medulloblastoma vs Ependymoma (7)

Answer 6

More common vs less commoin
Originate from vermis/FLOOR of 4th ventricle vs originate from ROOF of 4th ventricle
Can project into 4th ventricle, do NOT usually extend into basal cisterns vs Can extend into basal cisterns (toothpaste) and push through foramina of Luschka and Magendie
Homogenous vs heterogenous enhancement.
Calcifies less (20%) vs more (50%).
Linear “icing sugar” like enhancement of the brain surface

Question 7

SubEpendymal Giant cell Astrocytoma (SEGA) (4)

Answer 7

Associated with tuberous sclerosis.
Associated with renal AML or seizures/developmental delay.
Seen in kids, average age 11.
Arises from lateral wall of ventricle, near the foramen of monro, often causing hydrocephalus.
Homogenous enhancement.

Question 8

SEGA vs Subependymal Nodule (4)

Answer 8

SEN will stay stable in size, the SEGA will grow.
SEGA found in lateral ventricle, near the foramen of Monro, SEN can occur anywhere along the ventricle.
SEN is much more common.
Both can calcify.
Enhancing, partly calcified lesion at the foramen of Monro, bigger than 5mm, is a SEGA.

Question 9

Subependymoma (4)

Answer 9

Found in adults.
Well circumscribed intraventricular masses, most commonly at the foramen of monro and 4th ventricle.
Can cause hydrocephalus.
Typically don’t enhance. T2 bright like most tumours

Question 10

Central neurocytoma (3)

Answer 10

Most common intraventricular mass in an adult (aged 20-40).
“swiss cheese” due to numerous cystic spaces on T2.
Calcify a lot

Question 11

Choroid plexus origin tumours DDx (5)

Answer 11

Choroid plexus papilloma/carcinoma
Xanthogranuloma.
Mets.
Colloid cyst.
Meningioma

Question 12

Choroid plexus papilloma/carcinoma (4)

Answer 12

85% occur in kids, commonly before age 5.
Make up 15% of tumours in kids under 1.
Intraventricular mass, often making CSF, so causes hydrocephalus.
Brain tumours are usually supratentorial in adults and posterior fossa in kids. This tumour is an exception.

Question 13

Choroid plexus papilloma/carcinoma trivia (6)

Answer 13

Adults: 4th ventricle. Kids: lateral ventricle, usually trigone.
Carcinoma type is only seen in kids and therefore only in the lateral ventricle/trigone.
Carcinoma associated with Li-Fraumeni syndrome (p53 mutation)
Angiography may show enlarged choroidal arteries which shunt blood to the tumour.
Carcinoma type looks similar (unless invading the parenchyma) and almost exclusively seen in kids.
Usually solitary, can rarely have CSF dissemination.

Question 14

Xanthogranuloma (3)

Answer 14

Benign choroid plexus mass.
Seen in 7% of population.
They restrict diffusion.

Question 15

Mets (3)

Answer 15

Most common location of intraventriculr mets is trigone of lateral ventricles, because of blood supply to choroid plexus.
Most common primary is controversial, either lung or renal.

Question 16

Colloid cyst (5)

Answer 16

Almost exclusively seen in anterior part of the 3rd venticle, behind the foramen of Monro.
Can cause sudden death via acute hydrocephalus.
Varied appearance, depends what they’re made of.
If cholesterol, T1 bright and T2 dark.
If not, they can be T2 bright.
Round, well circumscribed mass in the anterior 3rd ventricle. Can be fairly dense on CT.

Question 17

Meningioma (2)

Answer 17

Can occur in an intraventricular location, most commonly (80%), at the trigone of the lateral ventricles (slightly more on the left).