History and examination\nA 42-year-old male with a history of right eye visual field abnormalities presented with recent visual disturbances of the right eye and intermittent headaches. The visual disturbances were described as intermittent spots of blurriness. Initial MRI with contrast showed an oval-shaped lesion within or abutting the right optic chiasm. The lesion demonstrated intrinsic T1 hyperintensity (Figure ), as well as susceptibility and increased T2 and fluid-attenuated inversion recovery (FLAIR) signal. In the subsequent months, the patient complained of worsening visual changes that included the left eye as well. Visual acuity was graded 20/30 OD, 20/20 OS, and visual field testing revealed a very small scotoma in the left lower quadrant of the right eye. Pupils were equal, round, and reactive to light. Color vision was within normal limits with 14 out of 14 color plates correctly named in each eye. A dilated funduscopic exam revealed the discs to be sharp and pink with a cup to disc ratio of 0.1 OD, 0.2 OS and no optic nerve pallor on either side. Extra-ocular motility was intact bilaterally. At this time, the patient was referred to our services and was diagnosed as a possible CM, with a differential diagnosis, including craniopharyngioma, meningioma, and arteriovenous malformation (AVM). Due to the eloquent location of the lesion and the risk of visual loss, observation was chosen over surgery. Two months after presentation to the clinic, the patient visited the emergency department due to headaches and further visual changes in the inferior fields of both eyes, citing increased blurriness specifically. Visual acuity worsened to 20/40 OD, with no visual field cuts and no papilledema bilaterally. The patient was started on corticosteroids. Repeat MRI showed an expansion of the right optic chiasm/nerve lesion with increased T1 hyperintensity compatible with acute hemorrhage (Figure ). The lesion extended posteriorly and laterally to abut the right uncus and right cerebral peduncle. Visual field deficits were present in about three-quarters of his vision in both eyes, including the left temporal field and the right inferior nasal field (Figure ). After discussing therapeutic strategies with the patient, the decision was made to operate because subsequent bleeding could have caused irreversible blindness in both eyes.\nOperation\nUnder general anesthesia, the senior author (EMD) performed a right pterional craniotomy for the resection of the right optic nerve and chiasm CM. Brain relaxation was performed by draining cerebrospinal fluid from the cisterns, making the opening of the Sylvian fissure unnecessary. The right optic nerve was identified microscopically and followed back to the chiasm, which showed purplish discoloration with hemosiderin staining. Discoloration was distributed along the superomedial aspect of the optic nerve on the right side and the posterior aspect of the optic chiasm. The CM was microdissected from the surface of the optic nerve without incising the nerve itself. The middle portion of the CM was densely adherent to the vasculature of the optic chiasm and nerve. Cauterization of the residual portion of the CM was completed, preserving the vasculature in order to reduce the likelihood of an ischemic event. Frozen and permanent specimens were sent to pathology. The frozen section returned as abnormal vessel and hematoma. Surgically, there was GTR; however, subsequent radiographic imaging provided evidence that the resection may have been subtotal (see discussion). Craniotomy closure occurred by the replacement of the bone flap and the reapproximation of the myocutaneous flap.\nPostoperative course\nThere were no immediate complications following the procedure. The permanent specimen returned as CM and three weeks postoperatively, the patient had regained approximately half of the vision that was lost and continued to improve (Figure ). MRI 12 months postoperatively showed no sign of recurrence (Figure ). Over two years after surgery, the patient had resumed all preoperative activities and reported significant visual recovery, with headaches occurring only once weekly. Thirty-two months after resection, MRI showed a small slightly lobulated area of T1 hyperintense material within the postoperative cavity along the right aspect of the optic chiasm (Figure ). This finding was new as compared to prior imaging and suggested that minimal recurrence in this location should be considered. Upon follow-up with ophthalmology, visual field deficits were stable. MRI at 39 months postresection showed previously seen small amounts of T1 hyperintensity in the central and right aspect of the optic chiasm with significantly decreased conspicuity (Figure ). Only a trace amount of T1 hyperintensity remained at the right aspect of the optic chiasm, suggesting the 32-month postop scan may have demonstrated a trace amount of subacute hemorrhage in the area suspected of being residual CM. During ophthalmological follow-up at three years, the patient mentioned having difficulty reading and more consistently occurring headaches since his office visit six months prior. Headaches were reported to be different than past migraines. When compared to older visual field testing, there was a worsening of deficits in the left eye but within the standard deviation. Visual acuity remained stable at 20/30 OD, 20/20 OS. The suspected residual CM will be followed with serial imaging and visual field tests with the possibility of additional surgical resection in the case of visual deterioration.
A 71-year-old male without significant medical history presented with sudden binocular diplopia and left frontal headache. Physical examination 48 h after onset of symptoms revealed a partial third cranial nerve palsy on the left side. Initial cerebral magnetic resonance imaging (MRI) demonstrated an 8 mm oval lesion in the anterior left interpeduncular cistern that was hyperintense on T1 and heterogeneous on T2-weighted images [ and ]. On the computed tomography angiography (CTA), the lesion enhanced but did not correspond to an intracranial aneurysm []. The patient was observed. Over the following week, the left third cranial nerve deficit worsened significantly. The ipsilateral pupil was fully dilated and unreactive. Complete ptosis and paralysis of the oculomotor nerve-related muscles were also observed. A second MRI showed ferromagnetic susceptibility signals on gradient echo images []. Constructive interference steady state (CISS) T2-weighted sequences better delineated the lesion and its relation to the oculomotor nerve []. The suspected diagnosis was CA of the third cranial nerve. Given the recent complete third nerve paralysis and the risk of recurrent hemorrhage, surgery was performed.\nSurgery was performed 2 months after onset of symptoms. Through a left subtemporal approach, exposure of the interpeduncular cistern revealed a raspberry-like lesion bulging from the third cranial nerve, anterolateral to the left cerebral peduncle []. A well delineated plane of dissection allowed removal of the lesion while preserving the integrity of the nerve [ and ].\nPostoperative computed tomography (CT) scan showed no complication []. Histopathological analysis showed a lesion with high vascularity and hyalinized channels lined by a single layer of endothelial cells, findings that confirmed the diagnosis of a cavernous angioma []. Six months after surgery, the patient remained with a complete oculomotor palsy.\nWe found eight surgical cases of oculomotor nerve CA [].[] Three patients presented with a pure oculomotor nerve deficit,[] two cases had mixed ophthalmic and oculomotor nerve symptomatology[] and one case had an optic nerve deficit in addition to ophthalmic and oculomotor nerve involvement.[] In two cases, despite the fact that the CA location was proven to be on the third cranial nerve intraoperatively, no oculomotor nerve deficit was found at presentation: One had only ipsilateral trigeminal symptoms[] and the other had pituitary dysfunction with ipsilateral optic nerve deficit.[]\nIn the six patients with oculomotor nerve palsy, three cases presented acutely with complete oculomotor nerve palsy in less than 24 h,[] two cases presented with a partial deficit that worsened to a complete palsy over 7-10 days[] and one patient developed slow progressive partial oculomotor palsy over a 6-month period.[] Cases with severe acute oculomotor nerve deficit at presentation had MRI findings suggesting intralesional hemorrhage such as hyper-T1 and hyper-T2 signals.[] Radiological findings of acute hemorrhage were not found in patients with a more slowly progressive symptomatology.[]\nSeven of the eight cases of oculomotor nerve CA had partial or total resection of the lesion []. Of the five cases with total resection, only one had recovery of nerve function with complete resolution of symptoms after 6 months.[] Of the remaining four patients without recovery, three did not have surgical preservation of nerve integrity.[] One case with partial oculomotor palsy developed immediate postoperative worsening after partial resection followed by subsequent improvement of nerve function.[] One case without preoperative oculomotor nerve deficit developed persistent oculomotor paralysis after partial resection.[]