Melanoma of the Choroid in a Dog

Intraocular tumors are rare in the dog. Of the reported neoplasms, melanomas are the most common. These tumors characteristically arise in the anterior uvea and secondarily infiltrate posteriorly into the choroid and/or anteriorly into the corneoscleral region. Advanced tumors may extend extraocularly. In the dog, isolated choroidal melanomas are extremely uncommon; to the authors' knowledge, only two cases have been previously reported. This report describes a pigmented choroidal tumor in a dog with clinical and histopathologic features resembling a benign melanoma.