Combination of lumbar kyphosis, epidural lipomatosis, and perineural cyst as a cause of neurological deficit: a case report.

We describe the rare simultaneous occurrence of epidural lipomatosis and a perineural cyst at the same level, lumbar kyphosis, osteoporotic vertebral fractures, and neurological deficits. A 75-year-old corticosteroid-dependent female farmer presented with severe low back pain, progressive lumbar kyphosis, and inability to stand because of numbness and muscle weakness of both legs. Plain radiographs displayed markedly decreased bone density, significant lumbar kyphosis, and vertebral compression fractures of L2, L3, and L4. Magnetic resonance imaging of the lumbar spine revealed a perineural cyst at the L2-3 level, extensive epidural lipomatosis, and spinal canal stenosis. Laminectomy from L3 to L5 with resection of epidural fatty tissue restored her walking ability. We postulate that the osteoporotic fractures and epidural lipomatosis were induced by corticosteroid therapy. Preexisting degenerative lumbar kyphosis of the type commonly seen in elderly farmers could have promoted osteoporotic lumbar vertebral fractures at points where bending stress had been strongly exerted. The combination of a perineural cyst and epidural lipomatosis at the same level has not been reported previously.