Acute Left-sided Foot Drop Attributed to Recurrent Synovial Chondromatosis of the Lumbar Spine

Abstract

Objective: To discuss an uncommon case of nerve root compression caused by synovial chondromatosis of the lumbar spine. Summary of background: Synovial chondromatosis is an uncommon, benign monoarthritic condition of the synovial lining of large joints of the body. It is considered a metaplastic process rather than a neoplastic one, in which nodules are formed from aggregates of chondrocytes in the synovium. The nodules cause non-specific symptoms such as pain and decreased range of motion in the affected joint. In rare instances, synovial chondromatosis has been known to involve the spine, with associated radiculopathy. We report a case of synovial chondromatosis of the lumbar spine, which to our knowledge is the first case with foot drop. Case presentation: A 58-year-old woman presented with symptoms of lower back pain with unilateral radiation, numbness, and tingling. After primary resection of an extradural cartilaginous mass in the region of L4-L5, her symptoms remitted. One year post-operatively, she experienced a progressive recurrence of her symptoms and the acute onset of foot drop. Re-excision provided partial symptomatic relief. Histopathology showed nodular aggregates of benign cartilage, consistent with synovial chondromatosis. Conclusion: Synovial chondromatosis of the spine is a rare but potentially challenging problem for both patients and clinicians. Due to the broad clinical presentation and vague imaging profile, preoperative diagnosis is difficult. The histopathologic findings must be correlated clinically to arrive at the correct diagnosis. Surgical removal may resolve the symptoms, though recurrence requiring re-excision is not uncommon. This is the fourth reported case of synovial chondromatosis involving the lumbar spine, and the first with recurrence resulting in an exacerbation of prior symptoms including foot drop.