[Elusive thoracic spine tumour. Report of an exceptional case and literature review].

Elusive tumours in the spine, most of them schwannomas of the cauda equina, have been reported very rarely. We present the case of a woman with a preoperative radiological diagnosis of schwannoma at D10 level in whom a laminectomy was performed to remove the tumour. Although the laminectomy was correctly positioned, there was no tumour upon opening the dura and the laminectomy had to be extended cephalad to find and remove the tumour. Mobile intradural extramedullary spinal tumours, the so-called «elusive tumours», occur very rarely, and it is exceptional when they are located in the thoracic spine. Knowing preoperatively which tumour is going to behave in this way is almost impossible. However, in the reported cases there are common features such as symptoms changing with different body positions, small tumour size and weak attachment to nearby structures. Neurosurgeons must be able to resolve this situation when confronted with a negative correctly-positioned laminectomy.