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 53-year-old woman was admitted to our institution complaining of a mild fever, severe headache, and progressive visual loss that had started 4 days before. On admission, the general condition of the patient and the results of the gross neurological examination were unremarkable. Goldmann perimetry testing showed bitemporal hemianopsia. Her visual acuity was 20/400 in the right and 20/200 in the left eye. A computed tomography scan showed a hyperdense, hemorrhagic mass measuring approximately 2.5 cm in diameter in the suprasellar region []. A magnetic resonance (MR) imaging scan [ and ] better outlined the mass: it affected both the pituitary stalk and the hypothalamus while reaching cranially the left Monro foramen and compressing the optic nerves and chiasm, a clear signal of an ongoing edema. Cerebral angiography showed no vascular malformation. The results of routine blood and serum examinations were normal. Endocrinological studies of the pituitary function were unremarkable. After 3 days, the patient underwent a gross-total resection of the lesion through an extended endoscopic, endonasal, transsphenoidal route. The resection of the lesion was combined with the opening of the third ventricle through the lamina terminalis. A careful reconstruction of the skull base was performed, with abdominal fat, nasal septal flap, and fibrin glue. After the operation, the visual symptoms improved immediately. On discharge, visual acuity was 20/50 in the right eye and 20/20 in the left eye. The patient had a transient incomplete hypopituitarism and mild diplopia which improved after few weeks. After 1 month, the neurological examination was unremarkable. Postoperative MR scan is showed in and . Histological findings confirmed the presence of a CM, showing hemosiderin, reactive fibrohistiocytic, ectatic vascular channels, and dilated cavernous spaces. On immunohistochemistry, the lesion was positive for CD34 staining, marker for endothelial lining, and was negative for elastin staining, thus ruling out an arteriovenous malformation. See showing the main steps of the endoscopic surgery.\nThe PubMed search engine () was used to perform an internet Medline literature research based on the following keywords “chiasma,” “optic,” “sovrasellar,” “CM,” “endoscopic,” and “transsphenoidal” with different combination. There were no limitations as to the timeframe, language, and publication type on the search process. We also cross-checked the references of the articles retrieved by looking for further papers of potential interest.