Most Orbital Incidentalomas Are Benign, but Rarely Malignant—Treatment Depends on Location and Symptoms

Professor Ho-Seok Sa of Asan Medical Center: “Safe to Observe If No Symptoms and Tumor Located Behind the Eye”

▲Professor Ho-Seok Sa from the Department of Ophthalmology at Asan Medical Center 

Recently, there has been an increase in cases where tumors are unexpectedly discovered in the orbit—the space behind the eye—during brain scans conducted for routine health checkups or headaches. However, clear treatment guidelines for these incidental orbital tumors have not yet been established. A domestic research team recently analyzed the characteristics and treatment principles of orbital pseudotumors and reported their findings to the academic community, marking the world’s first such report.

Orbital incidentalomas are masses or tumors around the eye that are discovered unexpectedly during tests for other conditions, without causing any noticeable eye symptoms.

Professor Ho-Seok Sa and his team from the Department of Ophthalmology at Asan Medical Center analyzed the clinical features and treatment outcomes of 43 patients in whom orbital incidentalomas were detected at the hospital.

The study found that most tumors were benign, although rare cases of orbital malignancies, such as lymphoma, were also identified. Tumors located at the back of the eye without symptoms could be safely monitored without surgery. In contrast, tumors situated toward the front of the eye, accompanied by noticeable eye protrusion or double vision, were recommended for surgical removal.

This research is significant because it provides treatment guidelines based on the type, location, and symptoms of orbital incidentalomas. By doing so, it helps reduce patient anxiety and avoid unnecessary treatments, ensuring that interventions are performed safely only when needed.

The research team analyzed 43 patients in whom orbital incidentalomas were detected at Asan Medical Center between March 2015 and July 2023. The most common circumstance of discovery was routine health checkups (48.8%), followed by examinations for headaches (27.9%) and dizziness (14.0%).

Although the patients did not notice any abnormalities prior to testing, detailed ophthalmologic examinations revealed that some already had mild symptoms: slight eye protrusion in 41.9% of cases, peripheral double vision in 21.4%, and drooping eyelids in 9.3%. Peripheral double vision occurs when objects appear doubled while looking sideways or up and down, even though vision appears normal when looking straight ahead. Drooping eyelids, or ptosis, refers to the downward displacement of the upper eyelid.

Most tumors were benign, including cavernous malformations—abnormal clusters of veins (55.8%)—and schwannomas, which develop along the nerve sheath (27.9%). Both cavernous malformations and schwannomas grow slowly and rarely cause pain. However, rare cases of orbital malignancies, such as lymphoma, were also identified, highlighting the need for careful evaluation.

Analysis of treatment outcomes showed that patients with tumors located deep in the back of the eye and no symptoms maintained stable tumor size in 96.6% of cases with regular observation alone, without surgery. In contrast, surgical removal was recommended for patients whose tumors were situated toward the front of the eye or who exhibited prominent symptoms such as eye protrusion or double vision. Tumors in the front of the eye were found to be more accessible surgically and could be safely removed with a low risk of complications.

Professor Ho-Seok Sa from the Department of Ophthalmology at Asan Medical Center emphasized, “Patients often feel considerable anxiety when orbital incidentalomas are detected, but most are benign and grow slowly. It is important to determine the most appropriate treatment for each patient. Rather than removing the tumor surgically by default, imaging should be used to distinguish the tumor type, and treatment should be guided by its location and symptoms.”

The study was published in the latest issue of ‘Scientific Reports’, a sister journal of ‘Nature’.