A 74-year-old woman presented with malignant progression of remnant epidermoid cyst manifesting as sudden onset of right ptosis and double vision. She had right oculomotor nerve paresis. She had a history of surgery for right cerebellopontine angle epidermoid cyst 20 years previously. T 1 -weighted magnetic resonance (MR) imaging demonstrated a hypointense mass lesion in the right cerebellopontine angle and basal cistern, and an isointense mass in the right paraclinoid region which was strongly enhanced. Diffusion-weighted MR imaging showed hyperintense areas in the right cerebellopontine angle, ambient cistern, and basal cistern, and the paraclinoid mass as hypointense. Surgery was performed using Dolenc's approach. Histological examination revealed that the paraclinoid tumor adjacent to the epidermoid tumor remnant was malignant transformation of epidermoid cyst into squamous cell carcinoma. She was treated with 46 Gy linac radiotherapy. She has been without tumor recurrence for 17 months. Malignant change of epidermoid cyst is extremely rare, but rapid progress of the symptoms suggests malignant transformation. MR imaging with gadolinium is useful for diagnosis.
The vasodilatory effect of intra-cisternal infusion of magnesium sulfate solution was evaluated in 10 patients with symptomatic vasospasm after aneurysmal subarachnoid hemorrhage (SAH) who underwent early clipping surgery. Cisternal drainage was installed in the prepontine and/or sylvian fissures. Carotid angiography was performed immediately after the onset of symptomatic vasospasm, then intracisternal infusion of 15 mmol/l magnesium sulfate in Ringer solution was started at 20 ml/hr and continued until day 14. Irrigation was performed from the cisternal tube (inlet) to the spinal drainage (outlet). The cerebrospinal fluid magnesium ion concentration (1.2 ± 0.2 mEq/l) significantly increased after the infusion therapy (6.0 ± 1.7 mEq/l, p º 0.001). Repeat angiography showed vasodilatory effect on the spastic cerebral arteries at 3 hours after the infusion, especially in the arteries near to the site of cisternal drainage placement. The magnesium infusion also caused decreased mean arterial blood velocity in the spastic arteries in 6 of the 7 measured patients (162 ± 38 cm/sec to 114 ± 42 cm/sec, p º 0.001). Finally, 5 of the 10 patients achieved good recovery, 1 patient had moderate disability, 1 patient became severely disabled due to meningitis, and 3 patients were vegetative or dead, due to failure of magnesium irrigation in 1 patient and advanced age in the other 2 (more than 80 years old). This preliminary study indicates that intra-cisternal infusion of magnesium sulfate solution has vasodilatory effect on the spastic cerebral arteries after aneurysmal SAH.
A 60-year-old female presented with occipital headache and limitation of neck movement. Neurological examination showed weakness of the right sternocleidomastoid muscle. Magnetic resonance imaging revealed a cystic lesion at the craniocervical junction and posterior compression of the brain stem. The lesion was totally removed through the transcondylar approach. The histological diagnosis was neu renteric cyst. The transcondylar approach provides a direct operative view of the clivus and anterior craniovertebral junction.
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