Pinpointing different types of tumors

Question 1

what is a periferal nerve sheath tumor sign?

Answer 1

A lesional pattern of T2 signal on MRI consisting of a central area of low intensity surrounded by a T2 hyperintense rim.

Question 2

Which is the most common tumor showing periferal nerve sheath tumor sign

Answer 2

Localized neurofibroma.

Question 3

How is schwannomas seen on CT?

Answer 3

Typically isodense to the brain and can be difficult to identify, depending on location. Cystic areas (usually found in larger tumors) are hypodense, similar to CSF. Following administration of contrast, they moderately enhance, often heterogeneously due to cystic areas.
Bone algorithm is excellent - Slow-growing they remodel the bone, with smooth borders, rather than destroy the bone

Question 4

What to look for in MRI for schwannomas?

Answer 4

the investigation of choice.
Exquisite anatomical details, which allows for precise localization of the tumor. This is particularly the case with high-resolution T2 sequences.

T1 C+ (Gd); prominent enhancement, heterogeneous in 70% of cases

Question 5

3 most common surgical paths for vestibular schwannomas

Answer 5

• Middle fossa approach
• Translabyrinthic approach
• Retrosigmoid approach

Question 6

When and why/why not middle fossa approach?

Answer 6

• laterally placed schwannomas. Small tumors (under 2.5cm)
  +
• Hearing preservation
• Good Exposure of IAC all the way to the geniculate ganglion.
• ## basically an extradural subtemporal approach
• potenital risk of damage to temporal lobe and seizures
• have to work around the facial nerve (risk of injury)

Question 7

What tumor? (pathognomomic finding)
* Child
* A compressed pituitary gland.
* A large intrasellar and suprasellar mass with cystic and enhancing components as well as calcifications.

Answer 7

Craniopharyngeoma

Question 8

Which is the most common lesion of the clivus?

Answer 8

Chordomas.