Papilledema Caused by a Thoracic Schwannoma

Increased intracranial pressure rarely occurs with spinal tumors at any level but is most common with upper cervical tumors (1). There has been no report of papilledema attributed to a thoracic schwannoma. A 54-year-old man had headaches and papilledema without other signs of nervous system dysfunction. Lumbar puncture revealed an opening pressure of 440 mm water, a protein level of 210 mg/dL, and a mild pleocytosis. Brain CT and MRI showed no abnormalities. Accordingly, we performed MRI of the spinal cord, which disclosed a T2-3 intraspinal tumor (Fig. 1). Surgical removal disclosed a schwannoma. One month after the operation, there was no headache, papilledema, or neurologic deficit. The lumbar puncture was not repeated.FIG. 1: Postcontrast T1 axial spine MRI at the T2-3 level shows an avidly enhancing intradural extramedullary mass (arrow) and displacement of the spinal cord (arrowhead).The five previously reported cases (2-6) of intraspinal schwannomas/neuromas and papilledema have included tumors of the cauda equina, cervical spine, and lumbar spine, but not thoracic spine. The pathogenesis of intracranial pressure elevation caused by spinal schwannomas is uncertain. It has been suggested that they may secrete protein kinase, which evokes synthesis of increased protein or that the protein represents a tumor breakdown product that interferes with absorption of cerebrospinal fluid (CSF) (7). Venous stasis caused by tumor compression of spinal or medullary venous plexuses producing an unfavorable transarachnoid villous hydrostatic pressure is another proposed mechanism that could lead to transudation of substances and further elevation of protein (8). Subarachnoid hemorrhage is described in about one-quarter of patients with spinal tumors and could be responsible for papilledema (9). Blockage of the CSF outflow by spinal arachnoid adhesions can also cause raised intracranial pressure (10). The spinal canal, acting as an elastic reservoir for CSF, is thought to be important in maintenance of a constant intracranial volume. By compromising this system, spinal tumors may reduce the capacity of this reservoir (11). Comprehensive spine imaging should be a part of the evaluation of a patient with papilledema who has normal brain imaging, especially if spinal fluid protein is elevated and even if there are no clinical manifestations of a spinal tumor. Xiao-jun Wu, MD Huai-rui Chen, MD Ju-xiang Chen, MD Yi-cheng Lu, MD Wei Huang, MD Department of Neurosurgery Changzheng Hospital Shanghai, People's Republic of China [email protected]