Foramen magnum tumors

Abstract

This study involved 57 patients with benign extramedullary tumors of the foramen magnum (19 neurinomas, 37 meningiomas, and one teratoma), who were operated on between 1957 and 1976. The 37 meningiomas represented 3.2% of 1139 meningiomas of the neuraxis. The initial neurological examinations of about half of these patients were unremarkable. The clinical presentation of tumors of the foramen magnum frequently mimics multiple sclerosis, cervical spondylosis, intramedullary tumor, syrinx, carpal tunnel syndrome, and even normal-pressure hydrocephalus. All operations were performed through a posterior approach, and two surgical deaths (3.5%) were recorded. No surgery for recurring of tumor was recorded. The follow-up review of 56 patients (98.2%) showed good functional results if the tumor was detected before severe neurological deficits occurred. The possible mechanism of the sensory symptoms and muscle atrophy of the hands is discussed, and the electromyographic findings are reviewed.

Surgical Experience With Skull Base Approaches for Foramen Magnum Meningioma.

“…2,4,5,10,11,15,16,24,26,27) Meningiomas in the foramen magnum area frequently elude early diagnosis because their ill-defined symptoms mimic cervical spondylosis, multiple sclerosis, syringomyelia, normal pressure hydrocephalus, amyotrophic lateral sclerosis, Chiari type I malformation, cervical disc disease, carpal tunnel syndrome, other intramedullary or extramedullary tumors, and even carotid artery stenosis. 17,20,23,32) Foramen magnum meningioma has been identified in our department since 1983, due to the introduction of CT in 1976 and MR imaging in 1983. Before then, the combination of neurological and neurosurgical expertise and available studies could not provide accurate evaluation of meningioma in the foramen magnum region.…”

“…8) The incidental finding of meningioma in the foramen magnum is understandable, considering the asymptomatic meningioma annual incidence rate of 5.8 per 100,000, 21) the relative low mean annual growth rate (12%), 12) the relatively capacious subarachnoid space in the foramen magnum, 16) and the bizarre symptomatology of extramedullary tumors located in this region. 32) The transoral approach provides direct access to the tumor without brain stem retraction and direct exposure, but there are various disadvantages including fusion necessary to restore the stability of the spine, mandibular osteotomy to gain access to the deep and narrow working space, a high rate of infection because of the contaminated surgical route, and CSF leakage (Case 1). 3,27,28) Furthermore, inadequate visualization of the lateral margins of tumor, impossible vascular control, in particular of the vertebral artery, and the difficulty in watertight dural closure are additional problems.…”

“…Before then, the combination of neurological and neurosurgical expertise and available studies could not provide accurate evaluation of meningioma in the foramen magnum region. 17,32) This study used a more limited definition of the foramen magnum, 16) so our experience with meningiomas arising from this region was necessarily limited. Other studies have extended the criteria for`f oramen magnum'' 11,29) or included foramen magnum meningiomas in posterior fossa meningiomas.…”

“…6) Foramen magnum meningioma is often identified only at an advanced stage due to the unusual and unrecognized pathognomonic symptomatology. 14,20,29,32) The complex anatomy of this area, together with the deep, central, and vital location, creates various problems for operative treatment, especially if the tumors are attached ventral to the neuraxis. 3,9) Total removal of foramen magnum meningioma is difficult and is associated with high rates of complications and recurrence even if performed by experienced surgeons, 18) and may result in high morbidity and mortality or incomplete removal.…”

Foramen magnum schwannoma with an unusual clinical presentation: case report

“…5 Most are meningiomas or schwannomas, and most of the latter are spinocranial in location. 3,4 The tumor in this patient was a spinocranial schwannoma.…”