Large, well-circumscribed lesion measuring ~9 x 5 x 7 cm, approximately rectangular in shape, located in the soft tissue deep to the deltoid muscle, in the septum between it and the teres minor and long head of the triceps. The quadrilateral space is involved, through which the posterior circumflex artery and axillary nerve pass. The lesion has a heterogeneous fat signal with areas that are hyperintense on T2WI and enhance with gadolinium.
Cystic changes in the greater humeral tuberosity.