I just had an MRI on my rt knee, ( with 2 knee replacements) for a huge growing HARD SOMETHING that has gotten bigger than my knee! it hurts, it swells, it rubs when i walk, can be seen thru my pants....a hemotologist was seeing me for iron IVs, b/c I ve been so anemic for quite some time and know one knows why! so I had complained about my knee while there, well, someone from his office called me today, to say it was a benign cyst, and that my dr would talk to me more about it at my next appt, which is in July. I m no doc, but don t you have to have tissue to be examined to determine if something is benign or not? what should I do?