What are the two histological types of craniopharyngioma, and which would this be?
The two types are adamantinomatous (typically paediatric) and papillary (typically adult). Additionally adamantinomatous is usually predominantly cystic and in 90% of cases demonstrate some calcification. As such this would be adamantinomatous.
What MR spectroscopy feature is supportive of the diagnosis of craniopharyngioma?
Cyst contents show a broad lipid spectrum, with an otherwise flat(ish) baseline.
What is the usual T1 signal of cyst fluid in craniopharyngiomas?
Signal intensity varies depending on cyst contents, and can appear hyperintense due to protein, blood products, and/or cholesterol (in the classic adamantinomatous type); in the papillary variety, solid components appear isointense on T1-weighted images.
MRI confirms the multicystic nature of the mass, but also demonstrates that the fluid is intermediate T1 signal and does not attenuate on FLAIR. Thin irregular contrast enhancement is also present.
MRS has been performed over a mixed solid/cystic area. As such it does not demonstrate the characteristic flat trace with dominant lipid peak.