Reason: activity in left shoulder noted on PET scan, please evaluate for abnormality. History: left shoulder pain There is a focus of signal abnormality situated at the level of the glenohumeral joint along the anterior margin of the subscapularis, beneath the coracoid, and deep to the tendon of the short head of the biceps, measuring approximately 1.7 x 0.9 x 2.2 cm (TR x AP x CC). It is isointense to skeletal muscle on T1-weighted images, isointense to skeletal muscle on the coronal oblique T2-weighted images and is slightly hyperintense on the fat suppressed T2-weighted images. It enhances following gadolinium administration. The differential diagnosis includes focal pigmented villonodular synovitis, perhaps within the subcoracoid bursa. We cannot exclude the possibility of a malignancy on the basis of this study, however. There is intermediate signal intensity along the undersurface fibers of the supraspinatus and infraspinatus suggesting mild fraying, but we see no fluid-filled rotator cuff tear. There are small cysts within the humeral head. Moderate osteoarthritis affects the acromioclavicular joint. Although this study was not protocoled for detailed evaluation of the glenoid labrum or tendon of the long head of the biceps, we see no fluid-filled labral tear. The tendon of long head of the biceps appears normal. There is a small amount of fluid within the glenohumeral joint and tendon sheath of the long head of the biceps which is not necessarily of any clinical significance.
Small soft tissue mass anterior to the subscapularis in the approximate location of the subcoracoid bursa with the signal characteristics as described above that may represent focal pigmented villonodular synovitis, although we cannot exclude the possibility of a malignant lesion on the basis of this study. Other findings as described above. Referral to orthopedic oncology is recommended.