Moyamoya syndrome associated with plexiform neurofibromatosis type 1 presenting with hemichorea

Dear Sir, Moyamoya disease is a progressive, nonatherosclerotic, noninflammatory, vaso-occlusive disease, which involves the terminal internal carotid artery (ICA) and its branches with the formation of small-caliber inefficient collaterals causing the characteristic “puff of smoke” appearance on digital subtraction angiography (DSA).[1] This moyamoya pattern has rarely been described in patients with systemic disorders such as neurofibromatosis (NF) 1, Down’s syndrome, or sickle cell anemia.[1,2] Herein we present the case of an adult patient with plexiform NF1 with Moyamoya syndrome who presented with hemichorea. A 45-year-old man with plexiform NF1 on the left side of his face, neck, and chest presented. He experienced a sudden onset of abnormal intermittent involuntary movements in the right upper and lower limbs for 10 months, which remained static since onset [Video 1]. He had no weakness or sensory complaints. {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1","caption":"","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_w2wog4hv"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} Upon examination, the patient presented café au lait macules, neurofibromas, and axillary freckling [Figure 1]. He displayed non-patterned dance-like, random, rapid, and flowy movements in the distal right upper and lower limbs. The rest of the neurological examination showed normal results. An Magnetic resonance imaging (MRI) with MR angiography (MRA) revealed a left thalamic infarct and attenuation of the right M1MCA with collateral formation [Figure 2]. DSA confirmed these findings [Supplemental Figure 1]. MR perfusion revealed reduced perfusion in both cerebral hemispheres, including the basal ganglia, with a greater reduction on the right side [Figure 2f]. This result confirmed a diagnosis of Moyamoya syndrome.Figure 1: Photograph revealing plexiform neurofibroma on the left cheekFigure 2: Axial FLAIR (a) and coronal T1- (b) and T2-weighted images (c) display a focal lesion (arrows) that appears hyperintense on FLAIR and T2-weighted images, and hypointense on T1-weighted image, indicating an infarct in the left inferior thalamus. Post-contrast coronal T1-weighted image (d) demonstrates focal enhancement within the lesion. Furthermore, a T1-hypointense lesion (dotted arrow in b) and a T2 hyperintense lesion (dotted arrow in c) are observed in the left infratemporal fossa. These lesions display patchy enhancement on post-contrast T1-weighted imaging (c). The maximum intensity projection (MIP) image of time-of-flight magnetic resonance angiography (TOF MRA) (e) shows non-visualization of the right middle cerebral artery (arrows). The arterial spin labeling (ASL) perfusion map (f) demonstrates bilaterally diminished perfusion in both cerebral hemispheres, including the basal ganglia, with a more significant reduction on the right side (arrows)NF1 diagnosis can be established in a patient who meets two or more of the following criteria: having six or more café au lait macules, axillary/inguinal freckling, two or more neurofibromas or one or more plexiform neurofibroma, optic nerve glioma, two or more Lisch nodules, a distinctive osseous lesion, a parent who meets the diagnostic criteria of NF1, and a diagnosed germline NF1 pathogenic variant.[3] Our patient fulfilled three of these criteria. The association of NF1 with Moyamoya syndrome is rare. Unlike most patients who are children and asymptomatic,[1] our patient was symptomatic. Post-stroke movement disorders develop in 1%–4% of all stroke cases.[4] Hemichorea-hemiballism is the most common post-stroke movement disorder in adults, whereas hemidystonia is the most common in children.[4] Xian et al.[5] identified abnormal functional connectivity between the basal ganglia-thalamus-cortical circuits using positron emission tomography (PET) and single photon emission computed tomography (SPECT) as important in the pathogenesis of chorea associated with moyamoya disease. The post-stroke movement disorder can present immediately or with a delay. In general, chorea appears first and resolves on its own, whereas dystonia and tremor manifest several months later. Our patient presented with non-self-limiting chorea, possibly due to persistent basal ganglia hypoperfusion associated with moyamoya syndrome. Revascularization surgery in moyamoya syndrome improves blood flow to the hypoperfused cortex and improves long-term neurological outcomes. We highlight the importance of recognizing vascular abnormalities associated with NF1 in young patients who present with post-stroke hemichorea. Timely detection is crucial to prevent recurrences and irreversible sequela. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Acknowledgement None. Author contribution Research project: Conception: PSB, AA, AG, DG, AKP, DMR, AKS Organization: PSB, AA, AG, DG, AKP, DMR, AKS Execution: PSB, AA, AG, DG, AKP, DMR, AKS Statistical analysis Design: PSB, AA, AG, DG, AKS Execution: PSB, AA, AG, DG, AKS Review and Critique: PSB, AA, AG, DG, AKS Manuscript preparation Writing of the first draft: PSB, AA, AG, DG, AKP, DMR, AKS Review and Critique: PSB, AA, AG, DG, AKP, DMR, AKS. All authors contributed towards the conception, writing and final reviewing of the manuscript. Ethical compliance statement The authors confirm that they have read the Journal’s position on issues involved in ethical publication and affirm that this work is consistent with those guidelines. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.