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 40-year-old female patient came to our attention with complains of sudden headache and vision loss. Examination revealed bitemporal hemianopia, diminished visual acuity in both eyes and nuchal rigidity. MRI showed multiple CMs, one of which localized in the optic chiasm, revealing recent bleeding \n[]. The patient had undergone four previous craniotomies at another institution for removal of bleeding CMs in different locations without sequelae. The senior author (JAMC) decided to perform emergent surgical exploration through a right pterional craniotomy, removing the clot and the lesion. Histopathological examination was reported as a CM. On the follow-up, the vision improved and the patient is capable of reading and driving, but 11 years after the surgery a right homonymous hemianopsia persists.