When ever I see something like this I usually think, what happened here? The first thought is that the owner backed his or her car over the poor thing after setting it down while loading other items into the trunk. But in this case, the seller tells us that the case is intact, so that rules that out.
My next scenario, based on personal experience, (fortunately not my own) is that the horn was laying out of the case, or in it's stand at the owner's residence, when the owner's wife or husband found out about a clandestine affair that the owner was involved in. At this time, the spurned husband or wife takes the horn in hand and turns it into a projectile, flinging it down stairs, or across the room, or possibly out the window. A friend of mine once returned home to find his brand new custom made electric bass floating in a bathtub full of water, courtesy of his wife, who had uncovered information about the man's love life that had inspired her actions.
I once saw a nice mk6 tenor in pretty much the same condition as this alto. It was at the repair shop of an old time Philly repair tech named George Sarkis. I looked at the horn and then looked at George. He could see the question in my eyes before I even asked it. He looked at me and simply said "too much cocaine." Seems that the horn's owner was playing a gig on the second floor in a loft when the drugs told him to throw his horn out the open window. What a waste.
Then there's the backing cars over the horns deal. Many years ago, a friend showed me his beautiful newly aquired mk6 soprano, one of the very early examples. It would have been in truely mint condition except for the fact that it was mangled. Poor thing was smashed flat. He told me that he had dropped it down his basement steps and it had landed on the hard concrete floor. A year of so later, he showed me the horn again, this time pointing, telling me, "yeah, that's where the wheel ran over it." So the truth came out. He was ashamed to tell me that he had ran over his own horn, concocting the stairs story. Later, he forgot to lie and told me the truth. Either way, it was a sad story.
Man, I hate to see 'em end up like this.
Julian