Unilateral Lesions of the Lacrimal Fossa: An Exploration of Lacrimal and Nonlacrimal Pathologies Through the Prism of a Solitary Fibrous Tumor

The lacrimal fossa, located in the superolateral orbit, is a shallow depression in the orbital plate of the frontal bone. It primarily houses the orbital lobe of the lacrimal gland but also contains other tissues such as fat, blood vessels, and nerves. Lacrimal fossa lesions constitute a diverse spectrum of pathologies, originating from the frontal bone and adjacent soft tissues or from the resident lacrimal gland itself. We present a 42-year-old woman with slowly progressive right superolateral orbital swelling. Subsequent resection of a mass lesion demonstrated a solitary fibrous tumor (SFT) with a Demicco risk of two. We use SFT as a springboard to review the differential diagnosis of unilateral lesions of the lacrimal fossa and lacrimal gland. Nonglandular lesions of the lacrimal fossa primarily arise from its bony superstructure, neurovascular supply, and/or connective tissues. In contrast, lacrimal gland pathologies are like those of the salivary glands, being primarily neoplastic or infectious/inflammatory. Neoplastic lacrimal gland lesions can be of epithelial origin or nonepithelial origin, with lymphoma being the most common of the latter. While inflammatory lesions are often bilateral, unilateral involvement can occur. The clinical and imaging characteristics of multiple unilateral lacrimal fossa and lacrimal gland pathologies are explored herein.