MyPACS.net: Radiology Teaching Files > Case 3292011

previously visited SYNOVIAL CYST LUMBAR SPINE L5-S1
Contributed by: Fritsch & Thompson, Radiologist, Diagnostic Radiology of Houston, Texas, USA.
Patient: 57 year old female
History:
SUDDEN ONSET OF LOW BACK PAIN AND LEFT LEG PAIN FOR 2 WEEKS.  PATIENT NON-RESPONSIVE TO CONSERVATIVE CARE.

Images:[small]larger

Fig. 1: APLS shows transitional segment and degenerative sclerosis of the zygapophyseal joints

Fig. 2: Lateral LS film shows degenerative changes and rudimentary IVD space at transitional level

Fig. 3: Lateral LS spot film shows degenerative changes and rudimentary IVD space at transitional level

Fig. 4: Left transverse process of the transitional segment joined to sacral ala

Fig. 5: Sagittal midline T1 image. Mass does not extend to midline. Rudimentary IVD space below transitional segment.

Fig. 6: T1 image to left of midline shows medial extent of low signal mass

Fig. 7: T1 image further to left of midline shows low signal mass adjacent to zygapophyseal joint.

Fig. 8: T2 image at sagittal midline

Fig. 9: T2 image slightly to left of midline shows high signal mass outlined by low signal peripherally.

Fig. 10: T2 image further lateral shows bright signal of fluid in zygaphophyseal joint

Fig. 11: FatSat sagittal midline image.

Fig. 12: FatSat sagittal image slightly left of midline. Bright central signal with low signal outline peripherally.

Fig. 13: FatSat sagittal image further to left of midline. Some bright signal at zygapophyseal joint compatible with effusion.

Fig. 14: T1 axial. Degenerative hypertrophy of zygapophyseal joints, ligamentum flavum results in central canal narrowing

Fig. 15: T1 axial. Low signal mass adjoining left zygapophyseal joint displaces thecal sac and obliterates normal fat signal surrounding nerve root.

Fig. 16: T1 axial. Low signal mass adjoining left zygapophyseal joint displaces thecal sac and obliterates normal fat signal surrounding nerve root.

Fig. 17

Fig. 18

Fig. 19: Joint effusion results in bright T2 signal

Fig. 20: Joint effusion and fluid filled synovial cyst with bright T2 signal.

Fig. 21

Fig. 22

Fig. 23

Fig. 24
Findings:

Extradural mass projecting from the anteromedial aspect of the right L5-S1 degenerated facet joint creating mass effect upon the thecal sac and the traversing right S1 nerve root in the lateral recess.

Also noted is an asymetrical transitional S1 segment (partial lumbarization) on both radiographs and axial MR images.

Diagnosis: L5-S1 SYNOVIAL CYST WITH FACET JOINT OSTEOARTHRITIS CREATING NEURO MASS EFFECT AND LATERAL RECESS STENOSIS UPON THE LEFT TRAVERSING S1 NERVE ROOT .
Discussion:

  • Also know as "facet joint ganglion cyst" this cyst forms from a degenerative facet joint.

  • General Pathology:


    • Thickened connective tissue and synovium.

    • Associated with degenerative disc and facet disease.

  • Etiology:


    • Stess loading on lumbar spine.

    • Facet osteoarthropathy

    • Joint fluid accumulation

    • Facet instability and hypermobility

    • Synovial proliferation

  • Clinical presentation varies:


    • Chronic low back pain

    • Radicular symponsm

    • Neurogenic claudication

    • Cauda equina syndrome

    • Myelopathy (in cervical and thoracic spine)

  • Demographics:


    • Age: > 55

    • Gender: Females > males

    • Ethnicity: No racial predilection
References:
Ref. Physician: Mary Doyle, DC

DIAGNOSTIC IMAGING - SPINE: Ross et al, 2005
further information on lumbar synovial cysts can be found at: http://www.medscape.com/viewarticle/536573

Case Of the Week: 11/23/2005

MRI Case of the Week: 8/09/06
Comments:
Synovial cysts can cause acute radiculopathy and does mimic herniated discs. (The phrase "ganglion cyst" may easily be misinterpreted as arising from a "ganglion" or neuronal in origin.) Synovial cysts are extra-axial, and thus extra-dural. They can present anywhere synovium is present, to cause mass effect. Surgical approach is addressed at decompression first; then subsequently, stabilization, such as those needed for C1-2 cruciate ligament synovial cysts. Often, in acute synovial cyst formations, the cyst contains synovial fluid in its liquid state. In chronic cases, the synovial cysts may "harden" and even calcify. Occasionally, synovial cysts may resolve spontaneously. Surgery is reserved as an option when conservative therapies fail. Peter J. Yeh, MD Gulfcoastbrainandspine.com.--Peter Yeh, 2005-11-23
Additional Details:

Case Number: 3292011Last Updated: 07-21-2009
Anatomy: Spine and Peripheral Nervous System   Pathology: Benign Mass, Cyst
Modality: Conventional Radiograph, MRAccess Level: Readable by all users
Keywords: synovial cyst, degenerative arthritis, extradural mass, lumbar spine

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