Ocular choristoma with heterogeneous mesenchymal differentiation and concurrent anterior segment dysgenesis in a neonatal Holstein calf.

A 1-day-old Holstein calf presented with central corneal opacity and thickening, and a polypoid lesion in the medial canthus of the left eye, leading to vision loss and enucleation. Grossly, a mass extended from beneath the cornea to the medial intraocular region. Histologically, the mass was composed of proliferative foci of diverse mesenchymal elements, including mature cartilage and adipose tissue, immature cartilage and bone, and proliferating spindle-shaped cells in a myxoid stroma. Anterior segment abnormalities, including iris hypoplasia, iridocorneal adhesion, angle malformation, and lens anomalies, were also observed. The animal was diagnosed with an ocular choristoma with heterogeneous mesenchymal differentiation and anterior segment dysgenesis (ASD). To the best of our knowledge, this is the first report of choristoma with ASD in cattle.