CASE 90
By: Dr. Aliya Sarhan Al Barwani.
HISTORY: 34-year-old female with right shoulder pain.
What are the findings?
What is the diagnosis?
What is the complication of this mass?
FINDINGS:
Coronal T2WI: There is a well define soft tissue mass in the Spino-glenoid notch. It shows fluid signal in T2WI.
Sagittal T1WI: Mild atrophy and fatty replacement in the infraspinatus muscle.
DIAGNOSIS:
Spino-glenoid notch ganglion cyst with compression neuropathy.
Complication: Compression neuropathy on the Suprascapular nerve with denervation of Supraspinatus and Infraspinatus muscles.
PEARLS AND DISCUSSION:
Infrequent finding on MRI. However, cystic masses in the spinoglenoid notch is an important diagnostic entity as they may cause a compression neuropathy of the suprascapular nerve. The cyst is either ganglion cyst or synovial cyst. Associated labral tear is not uncommon and mainly seen with SLAP tear.
Compression neuropathy of the supracapular nerve will cause denervation and pain of both Supraspinatus and Infraspinatus muscles, but if the compression occurs more distally, only the Infraspinatus muscle will be denervated. Features of muscle denervation are muscle edema in acute phase and muscle atrophy and fatty replacement in chronic phase.
FURTHER READING:
1. Tung GA, Entzian D, Stern JB et-al. MR imaging and MR arthrography of paraglenoid labral cysts. AJR Am J Roentgenol. (2000)
2. Ji JH and Shafi M. Inferior paralabral ganglion cyst of the shoulder with labral tear -- a rare cause of shoulder pain. Orthop Traumatol Surg Res. (2012)
3. Westerheide KJ and Karzel RP. Ganglion cysts of the shoulder: technique of arthroscopic decompression and fixation of associated type II superior labral anterior to posterior lesions. Orthop Clin North Am. (2003)
