We read with great interest the article published in the journal by Yamauchi and colleagues (2018) entitled ‘Choroid plexus AVM with anomalous origin of the capsulothalamic artery: a case report’.1 The authors report on the case of a 45-year-old man found to have an unruptured Spetzler Martin high grade arteriovenous malformation (AVM) of the left temporal horn, supplied by a capsulothalamic artery anomalously arising from the plexal segment of the left anterior choroidal artery. Intranidal aneurysm and deep venous drainage favored embolotherapy to stereotactic radiosurgery. The lesion was treated using transarterial embolization with N-butyl cyanoacrylate injected from the lateral plexal branch of the plexal segment of the anterior choroidal artery and lateral posterior choroidal artery achieving complete obliteration. Postoperative contralateral homonymous hemianopsia was attributed to left optic radiation injury, retrospectively believed to result from an anomalous capsulothalamic artery arising from the lateral plexal branch of the plexal segment of the anterior choroidal artery, initially thought to arise from the bifurcation of the anterior choroidal artery during superselective angiography.
The anterior choroidal artery originates from the choroidal segment of the internal carotid artery distal to the posterior communicating artery as one or several branches, and is divided into cisternal and plexal segments.2,3 The proximal trunk of the plexal segment of the anterior choroidal artery gives origin to the medial perforating branch and lateral plexal branch. It was classically believed the plexal segment of the anterior choroidal artery supplies the choroid plexus exclusively and is thus safe to embolize. However, neural branches have been described to arise from the medial perforating branch of the plexal segment of this vessel. Furthermore, although the capsulothalamic artery classically arises from the cisternal anterior choroidal artery, occasionally this vessel may originate from the proximal plexal segment. Thus this represents the first such case report of the capsulothalamic artery or a neural branch arising from the lateral plexal branch of the plexal segment of the anterior choroidal artery. The contemporaneous presence of an AVM and persistent trigeminal artery suggests the genesis of anomalous origin of the capsulothalamic artery occurring during early gestation, as a consequence of ischemic vasculogenic stimulation by flow diversion from parenchyma to AVM.
Choroid plexus AVM was first described in 1859 by Forster. Choroid plexus vascular malformations are posited to develop at the 30 mm length interval, when primitive crossing arterial and venous endothelial tubes separated by only two layers of cells are most evident in proximity to the choroid plexus, allowing for facile formation of aberrant arteriovenous connections. Choroid plexus AVMs usually occur in the lateral ventricles, most commonly in the glomus,4 occasionally in the third and fourth ventricles,5 and may involve adjacent parenchyma.
Choroid plexus AVMs most commonly present with intraventricular hemorrhage or subarachnoid hemorrhage, with other presentations including hydrocephalus, seizures and syncope.5 Rupture occurs as a consequence of hypoperfusion resulting in vessel necrosis or hypertension-induced vessel fibrinoid necrosis. Mortality and recurrent hemorrhage occur in approximately one tenth and one fourth of patients, respectively. Choroid plexus AVMs are often angiographically occult.4 Computed tomographic and magnetic resonance imaging exhibit improved sensitivity for initial detection, identifying acute hemorrhage and an enhancing nidus, although the lesion is not initially characterizable as an AVM.4 Supply and drainage are best delineated on digital subtraction angiography.4
We commend the authors on the successful treatment of a challenging case. Choroid plexus AVMs should remain in the differential diagnosis in patients with intraventricular hemorrhage. They are frequently angiographically occult and non-identification on angiography does not rule out the diagnosis. Anatomical variations of choroidal arteries and vascular supply and drainage may have important therapeutic implications and should be kept in consideration. Treatment options include surgical resection, endovascular embolotherapy and stereotactic radiosurgery, as well as perioperative neurocritical care management. Monotherapeutic endovascular embolization is safe in the absence of neural branches supplying critical parenchyma.
Declaration of conflicting interests
The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author received no financial support for the research, authorship, and/or publication of this article.
References
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