Breast Lump as an Unusual Manifestation of Massive Rotator Cuff Tear.

Acromioclavicular joint cysts have been reported in association with extensive rotator cuff tears. However, cysts related to rotator cuff pathology can aslo form in other areas. In this case report, we describe the presentation of a large breast cyst associated with rotator cuff arthropathy mimicking a rapidly enlarging breast tumor.