I uncovered this today via a referral:

(there's a word for that?)
Two, actually. There's also epicaricacy.

My understanding is that they are different. Misfortunes aren't necessarily the same as troubles.
I think I would use epicaricacy for something like someone slipping on a banana skin (a misfortune or accident), and schadenfreude for something relating to a persoanl trouble (although I suppose a car breakdown could be misfortune or trouble, so perhaps I'm talking rubbish).

this rubbish actually brought me some joy at the thought that someone is taking the trouble to establish shadings for these two words.