Response

Dear Dr Komiyama,

We appreciate Dr. Michael’s comments pertaining to our article. He has referred to the development of arteriovenous malformations (AVMs) and clinical course of ruptured choroid plexus AVMs. It is agreeable that his comments regarding the development and nature of AVMs represent traditional knowledge that is widely accepted. Actually, AVM in our patient might be formed during the early gestational period because of co-existing primitive trigeminal artery and the aberrant capsulothalamic artery.¹ Nevertheless, we should acknowledge that this established theory is, in fact, a mere hypothesis and is not supported by robust evidence. Indeed, some investigators have raised objections to this theory. Several recent reports have described de novo AVM, which suggests that some AVMs may develop postnatally.^2,3 Moreover, based on the clinical presentation of AVMs and results of antenatal ultrasound mass screenings, Komiyama et al. inferred that congenital AVMs are rare, except for some specific forms of AVMs, such as the vein of Galen aneurysmal malformations and dural sinus malformations.⁴ We believe that it is inherently difficult to verify any of these hypotheses or to determine the timing of the development of AVMs, unless mass screening angiography is performed in neonates. Other recent studies have revealed the relationship between the development of AVMs and genetic polymorphism.⁵ Future studies may help unravel the mechanism of formation of AVMs rather than the timing of their formation.

Shigeru Yamauchi

Shizuoka, Japan

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.