Benign Orbital Tumors.

The orbit contains many vital structures and tissues. Masses in this confined space can rapidly cause visually significant symptoms, up to and including irreversible vision loss. These masses may be neoplastic, inflammatory, or infectious. This article will review primary benign neoplasms of the adult orbit with a focus on epidemiology, pathogenesis, diagnosis, and treatment. While often discussed in the context of orbital tumors, neoplasms of the lacrimal gland, intraocular, and periocular tissues are outside the scope of this article. In addition to a careful history, understanding epidemiology and risk factors can significantly streamline further workup and eventual diagnosis of orbital tumors. Orbital Anatomy The orbit is a confined space with well-demarcated anatomical landmarks. The orbital cavities are generally symmetric, with parallel medial walls and tapering dimensions posteriorly to the apex. The medial wall of the orbit is composed of the ethmoid, lacrimal, maxillary, and lesser wing of the sphenoid bones. The lamina papyracea is the thinnest part of the orbit and separates the medial orbit from the ethmoid sinuses. The orbital roof comprises part of the frontal bone and the lesser wing of the sphenoid bone and contains the lacrimal gland fossa, the trochlear fossa, and the supraorbital notch or foramen. The thicker lateral orbital wall is composed of the zygomatic bone and the greater wing of the sphenoid bone. The lateral wall extends anteriorly to the equator of the globe, allowing for a temporal field of vision. Lateral wall landmarks include the lateral Whitnall tubercle, Whitnall ligament, and the frontozygomatic suture. The orbital floor is composed of the maxillary, palatine, and zygomatic bones. The maxillary division of the trigeminal nerve and the infraorbital artery travel along the infraorbital groove and canal. The optic canal, superior orbital fissure, and inferior orbital fissure contain the critical neurovascular structures of the orbit. The arterial blood supply of the orbit is via the ophthalmic artery, a branch of the internal carotid artery. Anastomotic branches in communication with the external carotid form a network to further supply the periorbital region. The superior and inferior ophthalmic veins provide the primary venous drainage of the orbit. Orbital masses can therefore cause significant cosmetic and functional disturbances of varying degrees depending on specific location and size. Knowledge of orbital anatomy in conjunction with judicious imaging is essential to diagnose and manage orbital tumors appropriately. Copyright © 2022, StatPearls Publishing LLC.

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