CASE 6728 Published on 15.05.2008

Glenoid labral cyst in a 14-year old swimmer with chronic left shoulder pain

Section

Musculoskeletal system

Case Type

Clinical Cases

Authors

Massimiliano Rossi, Alessandro Paolicchi, Stefano Giannotti, Marco Ghilardi, Claudia Giaconi, Carlo Bartolozzi

Patient

14 years, female

Clinical History
A 14 years old female patient with left shoulder’s pain. Her habits included regular swimming exercise . The history was negative for traumatic events.
Imaging Findings
A 14 years old female patient with left shoulder’s pain. Her habits included regular swimming exercise. The history was negative for traumatic events.
The MR imaging protocol included T1 weighted Spin-echo and gradient T2 weighted in axial and coronal plain.
All MRI were performed on a 1.5 T scanner utilizing a dedicated shoulder surface coil. Direct MR Arthrography was performed by starting with contrast material injection (6-8 cc gadopentate dimeglumine 1/250) into the gleno-humeral joint under aseptic conditions.
Artro-RM showed a cystic-appearing mass adjacent to the labrum. The mass (3cm in diameter) in a paraglenoid position extended into the suprascapular notch.
The lesion was of low signal intensity in T1-weighted sagittal sequences and of high signal intensity in T2-weighted sequences.
The supraspinatus, infraspinatus and humeral biceps ‘s tendons were normal. A surgical excision of the cyst was performed with resolution of the sintomatology.
Discussion
Cystic lesions near the gleno-humeral joint have been described by various authors as “ganglion cysts”, “ganglia” or “synovial cysts”.
The periarticular location and frequent surgical confirmation led us to confidently suggest the diagnosis of glenoid labral cyst.
These masses can cause shoulder pain, compression neuropathy of the suprascapular nerve, and atrophy of the supraspinatus and infraspinatus muscles. Cysts in the spinoglenoid notch (between the scapular spine and bony glenoid cavity that connects the supraspinatus fossa to the infraspinatus fossa) can compress the distal suprascapular nerve, which produces pain and denervation of the infraspinatus muscle. Cysts in the suprascapular notch can compress the proximal suprascapular nerve, which causes pain and denervation of both the supraspinatus and infraspinatus muscles. Labral cysts are very conspicuous on T2-weighted images because of their high water content, which likely explains the increased frequency of labral cyst detection with MR imaging. Ultrasound examination may show labral cysts, but routine ultrasound evaluation of the rotator cuff does not depict the spinoglenoid notch area where labral cysts usually occur.

The accuracy of CT for the demonstration of labral cysts is limited most likely because of similar attenuation values of the cyst and surrounding soft tissues and beam-hardening artefacts from the adjacent osseous structures.
Labral cysts often develop when labral or capsular tears allow joint fluid to be forced into the adjacent tissues by the intraarticular pressures of the glenohumeral joint. Labral cysts, therefore, may be an indicator of Iabrocapsular injury and instability. A similar mechanism has been accepted as the cause of meniscal cysts; horizontal meniscal tears allow joint fluid to be extruded into the adjacent tissues. Paraarticular cysts associated with labral tears also have been described in the hip joint. Other mechanisms of labral cyst formation are possible and indude cystic accumulation of fluid within a bursa or tendon sheath.
The most common location for labral cysts can be explained by the specific regional anatomy of the shoulder joint: the postero-superior capsule above the posterior band of the infenor glenohumeral ligament is an area of relative weakness when compared with the thicker anterior capsule.
This weakness may allow easier penetration by dissecting fluid. Once a cyst forms, it expands through the path of least resistance into the fibrofatty tissue.
This channels cysts originating from posterosuperior labral tears toward the spinoglenoid notch and the suprascapular notch. An alternative posterior pathway is along the gutter formed by the bony glenoid, the fibrocartilaginous glenoid labrum, and the origin of the infraspinatus muscle. The anterior path of least resistance is likely the recess between the labrum and anterior capsule and the subscapularis bursa. The treatment for eventual compression of the infraspinatus branch of the suprascapular nerve has included (1) rest, nonsteroidal anti-inflammatory medication, and physical therapy; (2) open excision of the cyst; (3) arthroscopic decompression of the ganglion and repair of the posterior-superior capsulolabral complex and (4) ultrasound or computed tomography-guided aspiration.
Differential Diagnosis List
Glenoid labral cyst
Final Diagnosis
Glenoid labral cyst
Case information
URL: https://www.eurorad.org/case/6728
DOI: 10.1594/EURORAD/CASE.6728
ISSN: 1563-4086