Reply:

We thank Dr Brinjikji and colleagues for the letter written in response to our recently published article, “Localized Marked Elongation of the Distal Internal Carotid Artery with or without PHACE Syndrome: Segmental Dolichoectasia of the Distal Internal Carotid Artery.”¹

We have read with interest the articles published by Brinjikji et al² and McLaughlin et al³ in recent years. In 2013, the latter reported “pure arterial malformations (PAM)” of the posterior cerebral artery in a young female adult and described them as dilated, overlapping, and tortuous arteries with a coil-like appearance and/or a mass of arterial loops without any associated venous component. Their reported lesion (showing a benign natural history) has a striking resemblance to lesions seen in some of our patients. In 2017, Brinjikji et al² reported a case series comprising 12 patients diagnosed with PAM located in different intracranial arteries.

To highlight the regionality of this phenomenon, we focused on cases of segmental involvement of the distal internal carotid artery. Although we have not drawn any pathogenetic conclusion about this morphologic aberration, we believe that publishing research about such lesions, including all intracranial locations, may improve the understanding of this type of lesion. Furthermore, we believe that the term “segmental intracranial dolichoectasia” better represents these lesions than the term “malformation” because a malformation accompanies a functional defect, which is not applicable in our cases. However, further research is necessary to determine an appropriate name for this lesion.

We thank Dr Brinjikji and colleagues for their comments on our article, as well as for sharing their experience and encouraging others to report similar cases for promoting a deeper understanding of this disease entity.