A 21-year-old man was admitted to our clinic with a sudden and progressive headache and binocular diplopia. His symptoms had appeared 2 months before his first visit to the clinic. He had also experienced a similar attack 6 months earlier, but he was in a good general condition. The neurological examination revealed right-sided abducens nerve palsy. A brain computed tomography (CT) scan was acquired, which showed a suspected lesion in the cerebellopontine angle. Brain CT angiography was also performed, which did not reveal any prominent findings. The brain MRI showed an extra-axial pontomedullary lesion with the classic appearance of a CM, that is, a reticulated salt-and-pepper core, surrounded by a halo rim []. With the diagnosis of brain stem CM with a history of multiple hemorrhages, progressive neurological deficit, and pial presentation of the CM, the patient was enlisted for the surgical resection of the lesion.\nThe patient underwent surgery using the suboccipital retrosigmoid approach with intraoperative neuromonitoring. The procedure was performed through general anesthesia as the patient laid in a lateral position, and his head was fixed in a three-pin Mayfield headrest. After opening the dura, a CM was detected, arising from the sixth cranial nerve, with no invasion to the brainstem or the surrounding tissues. Since the lesion could not be separated from the nerve and its integrity was unclear, we resected the CM by cutting the proximal and distal portions (before the Dorello’s canal) of the sixth cranial nerve []. Intraoperative monitoring was used to detect changes in the function of the nervous structure. Motor and somatosensory evoked potentials were normal during the surgery. Direct nerve stimulation of the sixth nerve was also performed during the surgery. The response to stimulation was normal when stimulating distal to the lesion and weak proximal to the lesion.\nThe greater auricular nerve (>3 cm) was harvested as an interposition nerve graft. An anastomosis was performed using a fibrin glue sealant, as end-to-end suture was impossible. One day after surgery, the patient showed complete sixth nerve palsy. He was discharged on the 4th postoperative day, without any neurological deficit, except for the right abducens nerve palsy. In the 5-month follow-up visit, he showed complete recovery of the cranial deficit and diplopia. The histopathological examination of the lesion demonstrated typical characteristics of a CM []. To determine the origin of the lesion, immunohistochemistry staining for the S100 marker was carried out, and the results showed the intraneural origin of the lesion []. The follow-up imaging was normal after 2 years, and the patient was symptom free during this period.
A 48-year-old female was admitted with a 6-month history of progressive decrease in the vision. At admission, the neurological examination showed bitemporal hemianopsia and a decreased pupillary reaction to light in both eyes. Fundus oculi examination showed a light papilla bilaterally. The patient did not complain of pituitary dysfunction.\nBrain magnetic resonance imaging (MRI) showed a 2 cm hypointense lesion on T2-weighted images inside the optic chiasm in the suprasellar region. On T1-weighted images, the lesion appeared as an intraaxial lesion inside the optic chiasm without contrast enhancement after gadolinium administration []. The patient underwent cerebral angiography that did not reveal any vascular malformation.\nSurgery was performed via a right pterional approach. The lesion was dissected out from arachnoid adherences and coagulated by using a quantum molecular resonance-based bipolar coagulation (Vesalius®). This device uses a relatively low temperature that does not exceed 45–50°C, having minimum effect on nervous tissues, nerves, and blood vessels. The cavernoma was shrunk and dissected out from the chiasma []. The postoperative course was uneventful. On the 5th day following surgery, the patient underwent ophthalmological examination that revealed improvement in vision on the left eye without changes in the visual field. The histopathological analysis of the resected lesion confirmed the preoperative diagnosis of CM. Five months following the operation, MRI showed complete removal of the vascular lesion [].