A uveal melanoma that arises from the iris. It is the most common primary malignant neoplasm of the iris. The majority arise in preexisting nevi. The disease is iris melanoma (MONDO_0004064, a Monarch Disease Ontology id). Also known as: iris malignant melanoma, iris melanoma (disease), malignant melanoma of iris, malignant melanoma of the iris, melanoma (disease) of iris, melanoma of iris, melanoma of the iris.