Results of comprehensive diagnostics of feline uveal melanoma

Abstract

According to available statistics, melanocytic neoplasia is the most common form of ocular tumor in cats, accounting for 67% of cases in an analysis of 2614 cases of primary ocular neoplasia. Feline diffuse iris melanoma (FDIM) is by far the most common form of melanocytic neoplasia of the eye. The purpose of the study was to conduct a comprehensive diagnosis of eye diseases and identify the features of the course of iris melanoma in cats. Study cats with iris hyperpigmentation underwent a complete ophthalmological examination - slit-lamp biomicroscopy, gonioscopy and indirect ophthalmoscopy. As a result of the research, it was found that 5 animals had hyperpigmented lesions, which look like flat brown spots on the surface of the iris. These precursor lesions are considered benign and are known as iris melanosis. In 10 animals, thickening of the iris, dyscoria, decreased pupil mobility, and dispersion of pigment in the anterior chamber were additionally detected; in 2 of them, involvement of the iridocorneal angle in the pathological process was observed, in 4 - secondary glaucoma, due to tumor infiltration of the iridocorneal angle. According to the results of computed tomography, 3 cats had metastases in the liver. During our studies, one cat underwent an iris biopsy to differentiate melanoma from pleomorphic lymphoma. In the remaining cases, a biopsy was not performed, since 9 patients with obvious pathological changes required enucleation, and in 5 patients monitoring of the pathological process over time was prescribed. Cats presenting for evaluation of hyperpigmented iris lesions should undergo a complete clinical and ophthalmologic examination, including gonioscopy.