Ocular malignant melanoma is characterized by an unpredictable course, and metastases may develop, after a long disease-free interval, anywhere in the body. The mediastinum, however, is a rare site of these metastases, and metastatic melanoma presenting as a large mediastinal mass is quite unusual. We report herein a peculiar case of a solitary, late metastasis of malignant ocular melanoma, manifesting as a sizable posterior mediastinal mass and presenting with paroxysmal atrial fibrillation. Transthoracic echocardiography, computed tomography scan findings, and surgical treatment and pathologic examination are described., (Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)