Pigmented villonodular synovitis of a lumbar intervertebral facet joint.

Background Context: Pigmented villonodular synovitis (PVNS) is a slowly progressive lesion of uncertain etiology that involves the synovial membrane of joints or tendon sheaths. Only rarely does PVNS affect the axial skeleton, where it arises from the vertebral articular facet joint. Its treatment and prognosis remains limited.
Purpose: To describe our management in a patient with PVNS and to review previously published cases.
Study Design: Case report.
Methods: This is a case report of a 59-year-old woman who presented left sciatica. Computed tomography (CT) imaging revealed a mixed sclerotic and lucent lesion affecting the left L4-L5 facet joint. Magnetic resonance imaging (MRI) demonstrated a diffusely infiltrative process that originated from the left inferior articular process of L4 vertebra with extension into the spinal canal. A total synovectomy with left L4 hemilaminectomy was performed. Left L5 root was decompressed with total microscopic tumor removal. Decompression of spinal canal and absence of the tumor was shown by MRI and CT scan after the operation.
Results: Complete resolution of the patient's complaints was achieved. Histopathological analysis was consistent with a diagnosis of PVNS.
Conclusions: The principle of surgical management of spinal lesions causing neurologic deficit is early surgical decompression. It is also important to totally remove the synovium, the origin of PVNS, to prevent the recurrence.