As Karsten said, you can export the tickets in a CSV file for further filtering and analysis, which you could then upload into some kind of word cloud program.
I also just wanted to mention (and full disclosure I work for them) but Insycle can help with this. You can generate a top-down view of your ticket descriptions, update them for consistency when it makes sense, export them, filter results for specific words or phrases, etc.
I've attached a screenshot below. This would give you a top down view of your current descriptions, then you could add additional features such as filtering by ticket close dates, words included in the description, tickets from specific customer segments, etc, in addition to the word cloud for getting a better idea of what your most popular ticket topics are.