I had an ultrasound down on a mass in my leg and it was found to have an echogenic ring with a hypoechoic center what is this? it is about the size of a pea and is tender to the touch.,

An : An echogenic ring with a hypoechoic center may represent a cyst or abscess. If it is red and tender i would favor abscess (infection) and suggest that you see a surgeon. If it is around the knee or ankle and isn't red, it is more likely a synovial cyst. Synovial cyst would be less urgent, but may also warrant an orthopedic surgery evaluation.