Volume 50, Number 1 (7/2011) (page : 54-6) Case Report
Foraminal Synovial Cyst Associated with Ankylosing Spondylitis
Heyun Sung Kim, MD1;Chang Il Ju, MD2; and Seok Won Kim, MD2;
1;Departments of Internal Medicine, 2;Neurosurgery, College of Medicine, Chosun University, Gwangju, Korea

Ankylosing spondylitis (AS) is frequently associated with inflammatory lesions of the spine and continuous fatigue stress fractures; however, an association with an intraspinal synovial cyst has not been previously reported. A 55-year-old man with a five year history of AS who presented with back pain and a right radiculopathy was admitted to the hospital. Five years previously, he underwent a percutaneous vertebroplasty for an osteoporotic L1 compression fracture, and was diagnosed with AS at that time. Plain radiographs showed aggravated kyphosis and a stress fracture through the ossified posterior element, below the prior vertebroplasty. Magnetic resonance images revealed a right foraminal cystic lesion at the L2-L3 level with effacement of the nerve root. A 1.6 cm cystic lesion that appeared to arise from the L2-L3 facet joint without direct communication was excised from the L2-L3 foramen. Pathological examination confirmed synovial cyst. The patient's symptoms resolved immediately after surgery except for a mild dysesthesia of the right leg. We report herein a rare case of foraminal synovial cyst associated with AS accompanying posterior element fracture with a review of literature. 

Key words : Synovial cyst;Ankylosing spondylitis.