Persistent hyperplastic primary vitreous in two piglets

Two Large Yorkshire piglets were diagnosed as persistent hyperplastic primary vitreous (PHPV). In case 1, the white cord-like structure extending from optic disc to lens was observed in the normal-sized right eye. Case 2 showed buphthalmos of the right eye. The internal structure of the right eye was unclear due to bleeding, but a white cord-like structure was slightly observed. In both cases, histological examinations revealed the fibrovascular cord-like structure in hyaloid vitreous. The retina was detached, and dysplastic nervous tissue was observed in anterior vitreous. Immunohistochemistry using various neural markers suggested that dysplastic nervous tissue was derived from the detached neural retina. By the characteristic macroscopic and histopathological features, both cases were diagnosed as PHPV. To our knowledge, this is the first report of swine PHPV.