Which pineal region tumours are most likely to have large cystic components?
Pineocytomas often have cystic components, but they are usually smaller and seen in older patients. Pineal germ cell tumours often have significant cystic components, especially non-germinomatous germ cell tumours, including teratomas.
Do you think this is an aggressive tumour?
It is difficult to say for certain, however the mass appears well defined, with little solid component and no convincing evidence of invasion into the adjacent brain.
How are intracranial teratomas divided?
They can be divided into two broad categories, intra and extra-axial, which differ in epidemiology and clinical presentation. Another method of classifying an intracranial teratoma is as mature, immature and mature with with malignant transformation.
A mature teratoma would be a good fit for this tumour. What feature should you seek to help strengthen the presumptive diagnosis?
Demonstrating a focal region of macroscopic fat (not clearly present in this case) would be very suggestive of the diagnosis.
What are the most common locations for extra-axial teratomas and how do they present?
They most commonly arise in the pineal or suprasellar regions, and present due to mass effect: obstructive hydrocephalus due to impingement on the mid brain, Parinaud's syndrome, optic chiasm compression etc...
Single images from an MRI of the brain demonstrate a very large mass is located in the region of the pineal gland with peripheral contrast enhancement. The cystic component is multi-loculated and each component demonstrates different signal intensity with some having fluid-fluid levels. There is compression of the midbrain and hydrocephalus.