This young healthy, right dominant patient had initially presented three years prior with pain and weakness of the right shoulder. At that time an MRI showed a paralabral cyst in the spinoglenoid notch and an electromyography investigation showed diminished conduction in the right infraspinatus muscle, presumably a consequence of suprascapular nerve entrapment by the cyst. He underwent an arthroscopic release of the spinoglenoid notch of the right shoulder along with the removal of the cyst. Arthroscopically the labrum was found to be intact. 

Currently, he presented with pain in the right shoulder and on the ventromedial side of the elbow. Orthopedic physical examination showed rotator cuff weakness and scapula alata on the right. An ultrasound showed subtle atrophy of the right brachialis muscle and electromyography showed very subtle diminished response in the brachialis muscle. The neurologist was consulted and physical examination found a subtle weakness in the right brachialis and triceps, whereupon the consulted neurologist requested an MRI of the cervical plexus and upper limbs.

A cervical plexus MRI, non-contrast MR of the right shoulder and MR of the upper limbs using the body coil was performed. This showed bilateral cysts in the spinoglenoid notch. The cyst on the right is presumably a recurrence of the previously operated cyst. The cyst on the left seems to be asymptomatic; the rotator cuff muscles on the left show no signs of denervation. We found no anatomical substrate for the very subtle brachialis weakness. 

A previous case report (referenced below) has described bilateral spinoglenoid notch cysts associated with superior labral tears.