What does asymmetric prominence of the right temporal horn?

It can be the sign of something or simply normal variation (nothing).

This finding is more useful if 1) it can be compared to a prior image and 2) If there were some symptom that that correlated

In 1:

-same as before probably means nothing

-different might mean something (and a future image might be worth getting based on symptoms or recommendation by a specialist, usually a neurosurgeon)

In 2:

-if the study was to "assess for hydrocephalus, shunt malfunction, severe headache with vomiting, etc" there's a good chance it means something and should be evaluated by a specialist (unless its not anything new based on prior imaging)

-if it was for anything else, like sinus infection, head trauma, regular headache, its probably nothing

In summary, if it was something your doctors were looking for, you might have found it. If it was unexpected, you found "nothing" on accident.