Uveal malignant melanoma in a duck.

An adult male Muscovy (Cairina moschata) X Peking (Anas platyrhynchos) duck had a primary malignant uveal melanoma with periocular extension involving the left eye. The periocular mass displaced the globe 1.5 cm laterally. Thoracic metastasis of the ocular neoplasm infiltrated the pectoral muscles, rib cage, and cranial lung lobe on the left side, causing diminished voluntary motion of the left wing. The left orbit was exenterated, but tumor regrowth was evident within 2 weeks. This case was unusual because melanocytic neoplasms are rare in birds.