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Case Six - Neurofibromatosis II

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Clinical History: The patient is a 17-year-old male with a five year history of neck and shoulder pain. There is intermittent numbness of the left upper extremity down to the elbow. The patient's pain is aggravated by activity, particularly running. Pain is also worse when he is lying down. No history of weakness. The patient also has history of multiple subcutaneous nodules which were biopsied and shown to be neurofibromas. There is no family history of neurological disease.

Findings:

Figure 1; T1weighted (TE20/TR600) sagittal image through the cervical spine demonstrates enlargement of the cervical cord with multiple areas of decreased signal intensity within the cervical cord.

Figure 2; T1 (TE20/TR600) post IV contrast sagittal image through the cervical spine demonstrates patchy enhancement within the cervical spinal cord.

Figure 3; T2 weighted (TE80/TR1800) sagittal image through the cervical spine demonstrates diffuse abnormal increased signal intensity within the cervical spinal cord as well as patchy areas of bright and dark signal intensity within the mid cervical spinal cord.

Figure 4; T1 weighted (TE14/TR576) axial image through the internal auditory canals demonstrates bilateral isointense soft tissue masses within the internal auditory canals.

Figure 5; T1 weighted (TE15/TR605) post IV contrast axial image through the internal auditory canals demonstrates abnormal enhancement within the internal auditory canals bilaterally.

Figure 6; T1 weighted (TE15/TR605) image after intravenous administration of gadolinium demonstrates abnormal enhancement of the right 5th cranial nerve.

Diagnosis: Neurofibromatosis II with bilateral acoustic neuromas, right 5th cranial nerve neuroma, and juvenile polycytic astrocytoma involving the cervical and thoracic spinal cord.

Discussion: Neurofibromatosis II is a neurocutaneous disorder or a phakomatosis which is autosomal dominant, associated with chromosomal abnormalities on chromosome #22. It is associated with multiple CNS tumors specifically cranial nerve schwannomas, meningiomas and spinal cord tumors. Also, nerve root tumors are also common in patients with neurofibromatosis II.

Bilateral acoustic neuromas are diagnostic of neurofibromatosis II. Cutaneous manifestations such as cafeaulait spots and cutaneous neurofibromas are much less common than in neurofibromatosis I.

The case presented not only has the diagnostic bilateral acoustic neuromas, there is also a trigeminal neuroma, the next most frequently involved cranial nerve. Schwannomas are typically isointense on T1 weighted images and iso to hyperintense on T2 weighted images. Marked enhancement after administration of contrast is typical.

The case presented did not have intracranial meningiomas even though this is a common finding in patients with NF2.

Spinal cord tumors are also commonly seen in neurofibromatosis II patients. Intramedullary ependymomas are most common. In the patient presented, a juvenile polycytic astrocytoma involved the cervical and thoracic portions of the spinal cord.

Other common intraspinal tumors in NF2 patients include peripheral nerve root schwannomas and spinal cord extraaxial meningiomas.

References:
Osborne AG: Diagnostic Neuroradiology. Mosby 1994; 84-93.

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Submitted by:
Donna Plecha, M.D.