Peritendinitis?

Hi, I posted a while back about a small lump I found under right ankle, on the outer side of my foot. It's about 1 cm in diameter, and feels firm. It's located directly below the ankle, and feels like its over a tendon. I recently had an MRI done of the ankle to determine what the lump might be. The radiologist report says that the lump is consistent with the findings of peritendinitis. I had seen an orthopedic surgeon about the lump a few months ago, and she said it was either a ganglion cyst or peroneal tuberosity and said nothing to worry about. I'm a little confused as these all seem like different diagnosis'. I have not had the lump biopsied. My question is.. can peritenditis cause a lump such as this? Should I seek a third opinion? Thanks... I'm 29 & female by the way.