Ductal Plate Malformations in Captive Snakes.

Ductal plate malformations are abnormalities in the liver that arise from inappropriate or incomplete remodeling of the embryologic ductal plate. Various types of ductal plate malformations are reported in the human and veterinary literature, most commonly affecting domestic mammalian species but also fish. We investigated the occurrence and described the histopathologic features of ductal plate malformations in captive snakes. Malformations were identified in 18 snakes: 10 colubrids, 6 vipers, and 2 boids. There was no sex predilection, and the mean age was 17 years. The majority of lesions were incidental with most snakes having one or more comorbidities, most commonly neoplasia or systemic inflammation, that resulted in natural death or euthanasia. Ductal plate malformations in all livers were broadly characterized by a well-demarcated nodule of irregular bile ducts embedded within a varying amount of fibrous stroma. Malformations were further categorized based on the amount of fibrous stroma and dilation of the bile ducts as von Meyenburg complexes, cystic liver disease, and/or an intermediate hybrid subtype representative of cysts arising within von Meyenburg complexes. Histochemical and immunohistochemical staining, including Gomori's trichome and pan-cytokeratin, respectively, were applied on select cases to confirm histologic features. Malignant transformation was not identified within this population.