A large intramuscular lesion is seen in the left axillary region, seen insinuating between the scapula and the posterolateral aspect of the thoracic wall. It measures 11 x 8.7 x 12 cm in AP, SS, and CC dimensions. It displays homogeneous high T1, and high T2 signals with complete homogenous suppression on T2 STIR, consistent with its fatty nature.
It has a smooth outline formed by a pseudocapsule of stretched muscle fibers of the subscapularis muscle.
- anterior relations: axillary neurovascular structures and pectoralis major muscle. The tendon of pectoralis minor is stretched at its anterosuperior surface
- posteriorly, scapula
- medially: lateral thoracic wall (ribs and lateral chest wall muscles)
- laterally: humeral head, glenohumeral joint, and axillary neurovascular bundle
- superiorly: coracoid process, clavicle, and pectoralis minor tendon
- inferiorly: axillary fossa containing neurovascular bundle and axillary fat
Features are in keeping with intramuscular lipoma of subscapularis muscle.