Synovial cyst

Case contributed by Assoc Prof Frank Gaillard


Past history of clival meningioma. Now 'numb hands'.

Patient Data

Age: 65
Gender: Male

There is T2 mildly hyperintense, T1 hypointense mildly enhancing lesion within the central inner aspect of the left C7 lamina. This has a maximum transverse diameter of 9.3 mm. This is contiguous with an extraosseous cystic component in the left posterolateral aspect of the spinal canal measuring 6 mm AP x 5.7 mm transverse. The latter exhibits T2 central hyperintensity with a rim of hypointensity and demonstrates rim of enhancement. On the correlative CT images, the extraosseous intraspinal canal component shows a rim of incomplete calcification. The adjacent left C7/T1 facet joint shows degenerative changes with severe loss of disc space height and subchondral sclerosis. Consequently there is moderate compression of the left hemicord at C7 level.


There is partly osseous partly extraosseous cystic lesion related to left C7 lamina with moderate compression of the left hemicord at C7. The imaging appearances are most probably of a degenerative intraspinal cyst (subchondral cyst versus a ganglion).


Degenerative disc disease between C3 and T1 being most marked at C5-6.

At C7/T1 there is 2.5 to 3 mm of anterior subluxation of C7.

Closely related to the superomedial aspect of the left C6/7 degenerative facet joint, there is localized well-defined destruction of the C6 lamina by a lesion which appears to have a thin rim of calcification anteromedially where it is indenting the left side of the cord and is high likely to be impinging upon at least the left C7 nerve roots. The size of this lesion within the canal is 6 mm and the corresponding area of well-defined bony loss in the lamina measures 4 mm.

The contralateral facet joint space is narrowed with local erosions, and similar multilevel facet joint changes are shown.

The appearances are in keeping with long-standing lesion, most likely a degenerative synovial cyst related to the left C6-7 facet joint, on a background of severe facet joint disease with erosions.

Case Discussion

Patient went on to a laminectomy. 



1. The sections include ligamentum flavum, connective tissue and lamellar bone. A cyst is present, which is lined by synovial cells and some multinucleated giant cells. The lumen contains fibrinoid material. There is no increased acute inflammation. No granulomas are seen. There is no evidence of malignancy. The features are those of a synovial cyst.

2. The sections contain ligamentum flavum, connective tissue and lamellar bone. No cyst or tumor is seen.


  1. Dural mass: synovial cyst.
  2. Extradural tissue: no significant abnormality seen.


It is important not to forget synovial cysts as a cause of peripherally enhancing masses in the extrathecal space, anywhere along the spinal canal, but particularly in the lower lumbar and midcervical regions. 

PlayAdd to Share

Case information

rID: 33858
Published: 30th Jan 2015
Last edited: 1st Jul 2020
System: Spine
Inclusion in quiz mode: Included

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.