Hi,
I just signed up to monsterfishkeepers after reading this thread.If the following description is what your fish has I can tell you how to cure it...........
just behind the pectorial fin starting right at the base, a growth began as small greyish to pinkish in colour, looking like what i imagine a tumor would look like, almost brain like in appearance! and growing slowly, if that makes sense?
two of my group of angels had this growth a few months back, I seperated them from the group and treated them with a course of 'esha 2000' within a week the growth seemed to shrink another week later and were 90% gone.
on one fish it came back a few months later and required a second ,and never again appeared on the second fish.
hope this helps,
regards
joe mc