Orbital Vascular Anomalies: A Nomenclatorial, Etiological, and Nosologic Conundrum

Vascular anomalies are a heterogeneous group of disorders that frequently present in the periorbital region. They encompass 2 broad entities: vascular tumors, which possess a proliferative endothelium, and vascular malformations, which are basically localized defects of vascular morphogenesis. The primary goal of this review was to address inaccurate or controversial terminology in the oculoplastic literature concerning orbital and periorbital vascular anomalies and to categorize these lesions in an abridged and simplified hierarchical list that adheres as much as possible to the most recent (2018) iteration for the classification of vascular lesions proposed by the International Society for the Study of Vascular Anomalies (ISSVA). The secondary goal of this review was to review and update information regarding the genetic underpinnings of vascular anomalies and the downstream signaling pathways that are subsequently affected as a result of these genetic errors.

A literature review was conducted in PubMed, MEDLINE, PubMed Central, National Center for Biotechnology Information Bookshelf, and Embase for several related keywords including "vascular anomalies, vascular malformations, vascular tumors, and cavernous venous malformation," both with and without adding the keywords "eyelid," "orbital," and "periorbital." In addition, a detailed search was conducted for controversial or obsolete keywords like "cavernous hemangioma," "lymphangioma," and "varices," again in their systemic and orbital/periorbital context.

Crucial issues in the 2018 ISSVA classification regarding the proper categorization of orbital vascular anomalies, particularly venous lesions, were critically evaluated and revised, and a regional, simplified, and abridged modification of the ISSVA 2018 classification was proposed.

Interdisciplinary and intradisciplinary dialogue concerning orbital vascular anomalies is seriously compromised due to the lack of a unanimous agreement on terminology and the absence of a unified classification concept system. The authors recommend that oculoplastic surgeons adopt ISSVA terminology whenever technically possible and scientifically sound. However, they also propose modifying the ISSVA 2018 classification specifically to adapt to the peculiarities of vascular anomalies in the periorbital region. At present, the simplified classification proposed here is a preliminary first step towards managing patients with orbital vascular anomalies with greater diagnostic and therapeutic precision, until such time in the future when the entire genetic makeup of orbital vascular anomalies is more completely elucidated. Optimistically, this could pave the way for a more robust classification and the ultimate therapeutic cure.