Rosai-Dorfman disease (RDD) is a rare histiocytosis that typically presents with painless lymphadenopathy but can also present with neurologic symptoms. c Sometimes described as a non-neoplastic lymphoproliferative disease, RDD often has a favorable prognosis. c Histology can be pathognomonic for RDD when lymphocytes are found embedded in the cytoplasm of macrophages, a phenomenon termed emperipolesis.Oy-sters c RDD of the nervous system can be challenging to diagnose as it often presents with isolated and nonspecific neurologic symptoms. c RDD affecting the nervous system can be mistaken for meningioma, as both typically present as a uniformly enhancing extra-axial mass. RDD should be considered in the differential diagnosis for a mass resembling meningioma on imaging. c RDD can co-occur with autoimmune diseases including systemic lupus erythematous, arthritis, or autoimmune hemolytic anemia; its relationship to immunoglobulin G (IgG) 4-related disease remains to be clarified.A 61-year-old woman with a medical history of Bell palsy, carpal tunnel syndrome, and remote hepatitis B infection presented to the hospital with right eye visual blurring. Six weeks before this presentation, she had a new severe headache in the right periorbital and temporal areas. She had also experienced burning pain in the distribution of the trigeminal nerve and dysesthesia in the right forehead when brushing her hair. The headache and dysesthesia had spontaneously resolved the week before presentation to the hospital. The patient's visual examination was normal despite subjective mild right eye blurriness. On further cranial nerve examination, she did not endorse dysesthesia, allodynia, or decreased sensation in the trigeminal nerve distribution. The remainder of the cranial nerve examination, the motor examination including deep tendon reflexes, and the sensory, coordination, and gait examination were all unremarkable. The patient's visual changes self-resolved after 2 days without treatment.

We report a 34-year-old male with a previously uninvestigated lifelong blindness of the right eye from compressive optic neuropathy secondary to congenital herniation of the gyrus rectus (HGR). His past medical history was otherwise unremarkable, with no history of prior head or ocular trauma. On examination, he had no light perception in the right eye, right relative afferent pupillary defect (RAPD), and primary optic atrophy. His left eye had normal visual acuity, color vision, and a healthy optic disc. There was a sensory exotropia in the right eye; however, extraocular movements were intact and the remainder of his neurological exam was normal. MRI revealed compression of the prechiasmatic right optic nerve from HGR and atrophy of the right optic nerve and optic chiasm (Figures 1 and 2), without any parenchymal mass lesions. There were no signal abnormalities in the optic nerves or the chiasm.

Idiopathic intracranial hypertension is a rare neurological disorder characterized by increased intracranial pressure, which can lead to visual loss and headaches. While medical therapy exists, weight loss is the only disease-modifying treatment. Weight loss is the only therapy that leads to sustained resolution of papilledema. Involving the patient in their disease management through patient engagement is a way to improve disease outcomes, and strengthen the therapeutic relationship. This feature discusses an overview of the disease, a patient's experience, and a physician's perspective.

Background: Conjugate horizontal eye deviation away from the side of the lesion, termed Wrong Way Eyes (WWE), is a rare manifestation of supratentorial lesions. The proposed etiologic hypotheses include seizure activity, compression of contralateral horizontal gaze pathways from mass effect or midline shift, and asymmetry of hemispheric smooth pursuit mechanisms. We present neurophysiological evidence that favors the asymmetry of hemispheric smooth pursuit hypothesis. Methods: Electroencephalography (EEG) was performed in 2 patients with large left hemispheric supratentorial lesions, capturing fluctuating periods of (a) unresponsiveness with WWE and (b) relative alertness without WWE. One patient had 5 days of continuous EEG, and the other routine EEG. Results: Neither patient had seizures. EEG showed normal right hemispheric activity during both unresponsiveness with WWE and alertness without WWE states. By contrast, more severe left hemispheric dysfunction was evident in the WWE state compared with the non-WWE state in both patients. In one patient, during the relatively alert state, right-beating nystagmus was observed, and drift of the eyes away from the side of the lesion was reliably seen to occur on eyelid closure and after ipsiversive volitional saccades. Conclusions: Seizure activity does not account for WWE. Compression of contralateral horizontal gaze pathways is also unlikely to account for WWE as that hypothetical mechanism should produce EEG abnormalities over the nonlesioned hemisphere, which were not seen. The findings suggest instead that a single dysfunctional hemisphere is sufficient to produce WWE. The repeated rightward drift of the eyes and nystagmus seen in one patient during relative alertness, and the observation of unilateral hemispheric dysfunction on EEG during unresponsiveness with WWE in both patients supports the idea that an imbalance of smooth pursuit mechanisms is most likely to account for this rare phenomenon.