Background: Malignant melanoma predominantly occurs in whites, and is potentially fatal. Distant metastases often occur in lung, liver, brain, and could occur without prior regional disease. Conjunctival melanoma metastasis to contralateral orbit has never been reported.
Patient presentation: A 60-year-old man who underwent a left primary conjunctival neoplasm resection 11 months ago presented for the evaluation of a conjunctival dark-colored mass with a bulging left lower eyelid that directly invaded the orbits bilaterally. A histopathologic examination and immunohistochemistry confirmed metastases from conjunctival melanoma. In addition, the contralateral orbit had metastases without local recurrence after surgery within the authors' department. The patient was given adjuvant therapy (vincristine + nedaplatin + dacarbazine) for 5 cycles, but he died 8 months after surgery.
Conclusion: Malignant conjunctival melanoma may metastasize to the contralateral orbit. A histopathologic evaluation should be mandatory in patients with medical histories of malignancy to differentiate new primary tumors, metastases, and benign tumors.