A-41-year old man presented with violent thunderclap headache and a bilateral proprioceptive sensibility deficit of the upper limbs. Cerebral CT scan and MRI were negative. Lumbar puncture confirmed subarachnoid hemorrhage (SAH), but cerebral angiography was negative. Three months later, the patient presented with paraparesis, and a thorough work-up revealed a diffuse, anaplastic extramedullary C7-D10 ependymoma with meningeal carcinomatosis considered the source of hemorrhage. The patient went through a D5-D8 laminectomy, temozolomide chemotherapy, and radiotherapy. The situation remained stable for a few months. In this paper, we would like to emphasize that spinal masses should be considered in cases of SAH with negative diagnostic findings for aneurysms or arteriovenous malformation.