Abstract Listings 2026

Purpose

Metastatic tumour of the orbit is exceedingly rare, accounting for 1-13% of all orbital tumours, while isolated metastasis to the extraocular muscle (EOM) is even rarer, affecting only 5% of metastatic orbital tumours. Melanoma represents only 5-15% of all metastases to the orbit.

Methods

Herein we describe a rare case of metastatic melanoma spread to the EOM.

Results

An 81-year male with a background of well-controlled Rheumatoid Arthritis on Methotrexate attended for routine follow-up for previous superficial spreading melanoma. The primary site was his left forearm (stage IIa) which was managed with wide local excision. Three years later he was found to have a recurrence on his left elbow crease with biopsy confirming metastatic melanoma. A subsequent staging CT demonstrated an intraconal lesion arising from the lateral rectus muscle of the left orbit as well as lung involvement. Although the patient remained asymptomatic with regards to his eyes, a biopsy of the EOM lesion was taken and confirmed metastatic malignant melanoma. A further MRI revealed brain metastasis and hence an MDT decision was made to prioritise systemic therapy including immunotherapy and stereotactic radiosurgery. However, there was failure to respond to treatment and disease progression was noted on subsequent brain scans and unfortunately the patient passed away due to metastatic melanoma related complications around 8 months after his presentation with recurrence of the melanoma.

Conclusion

We report an exceedingly rare example of an incidental finding of metastatic melanoma in a patient with an EOM mass. With ever increasing rates of melanoma, this case highlights the importance of ruling out orbital metastases in patients with a history of melanoma. Treatment is challenging and hence early detection is required with a low threshold for a diagnostic biopsy.

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