The authors reported complete regression of a large hemorrhagic lumbar synovial cyst
following posterior spinal fusion without direct cystic resection. A 64-year-old woman
suffered from sudden onset of the left buttock pain radiating to the left leg after
waking up in the morning following the previous history of a minor accident 2 months
ago. Magnetic resonance imaging (MRI) of the lumbosacral spine showed a large extradural
round mass originating from the left facet joint at the level of L3–L4. The mass was
hyperintense on T1-weighted images and hypointense on T2-weighted images, probably
compatible with hemorrhagic joint-related cyst. Surgical treatment was chosen for
her because of persistent left radicular pain with no responding to medications. The
patient underwent decompressive laminectomy, subtotal facetectomy, instrumented fusion,
and only tissue biopsy due to severe adherence of the mass and dura. Histopathological
examination was consistent with a hemorrhagic synovial cyst. The radicular pain completely
disappeared after the surgery. Follow-up MRI of the lumbosacral spine obtained 6 months
after the surgery demonstrated complete resolution of the hemorrhagic cyst. Complete
resolution of hemorrhagic synovial cyst seems to correlate with subtotal facetectomy,
probably resulting in leakage of cyst content and subsequent resorption of the cyst
wall. In addition, hematoma within the synovial cyst may resolve spontaneously over
time.
Key-words:
Hemorrhage - juxtafacet cyst - lumbar synovial cyst - spinal fusion - spontaneous
resolution