Not to be gross...but I would genuinely be interested in seeing posted pictures of the autopsy....especially if you think you've found something.
I've not had a large enough fish to perform an autopsy on, but I've often considered it. I have a dissecting microscope for the job. If any of my current fish die mysteriously like that, I'll certainly be having a good look.
I suppose we should be saying "necropsy". Here's a link I found that discussed what you might see and what it might mean:
http://www.koivet.com/handouts/akcanecropsy.doc
__________________
400 gal reef. Established April, 2007. 3 Sequence Dart, RM12-4 skimmer, 2 x OM4Ways, Yellow Tang, Maroon Clown (pair), Blonde Naso Tang, Vlamingi Tang, Foxface Rabbit, Unicorn Tang, 2 Pakistani Butterflies and a few coral gobies
My Tank:
http://www.canreef.com/vbulletin/showthread.php?t=28436