Neurinomas are common space-occupying lesions located in the spinal canal. Many reports concerning their clinical characteristics, diagnoses, treatments, and operative results have been published. Some case reports have discussed spinal neurinomas located at the cauda equina level. However, there is little information on their natural history. Here, we report a case of spinal neurinoma located at the cauda equina level, which caused normal pressure hydrocephalus (NPH). All symptoms resulting from the NPH were resolved by tumor removal. These findings suggested that if a spinal neurinoma located at the cauda equina level causes symptoms due to NPH, then removal of the tumor should be considered, when appropriate removal procedures are possible.key words: neurinoma, cauda equina, normal pressure hydrocephalus
Case Reportan 82-year-old man with hypertension complained of months of progressive gait disturbance, dementia, and intermittent urinary incontinence, without headache. Physical examination revealed moderate muscle atrophy in both limbs, hypesthesia of the lateral side of both thighs, and decreased patella and achilles tendon reflexes. Computed tomography (CT) of the head revealed ventricular dilatation (Fig. 1a). a lumbar puncture was performed. The cerebrospinal fluid (CsF) pressure was 100 mmH 2 O, and it appeared xanthochromic. CsF analysis showed a high protein level (0.667 g/L) and normal cell counts (9/3 cells/mm 3 ). Lumbar spinal magnetic resonance imaging (mRi) were conducted in order to examine the patient for normal pressure hydrocephalus (nPH), and the imaging demonstrated a well-demarcated intradural tumor in the cauda equina at the L1-L2 level (Fig. 1B). The tumor, which exhibited marked enhancement after the intravenous administration of gadolinium, compressed the nerves at the cauda equina level. CT myelography revealed total blockage of the CsF by the tumor (Fig. 1C).The patient underwent an operation for tumor removal. after a posterior L1-L2 laminectomy and a Th12 partial laminectomy, the dural sac was opened, and cloudy arachnoid membrane at the caudal side of the tumor was found (Fig. 2). after dissection of this arachnoid membrane, the tumor compressed the nerves of the cauda equina. The CsF from the caudal side of the tumor appeared cloudy and xanthochromic. However, the CsF on the cranial side of the tumor appeared watery clear and colorless. The tumor had arisen from a root of the cauda equina, and electrical stimulations confirmed that the root was not a motor root of the limbs. Total removal was performed including the root. a histological examination of the tumor showed typical features of a benign neurinoma (Fig. 3a, B).Postoperative neurological findings were marked by the progressive recovery of recent memory loss, sensory deficits of the lower limbs, diminished limb reflexes, and persistence of urinary disturbances. Total removal of the tumor was confirmed with CT and mRi (Fig. 4B). a lumbar puncture was performed 2 weeks after the surgery, and CsF analysis showed a de...
