Cholangiocarcinoma in a 4-month-old double yellow-cheeked Amazon parrot (Amazona autumnalis).

A cholangiocarcinoma was diagnosed in a 4-month-old double yellow-cheeked Amazon parrot (Amazona autumnalis). Histologically, neoplastic cells effaced hepatocellular architecture. Ultrastructurally, variably dilated bile ductules were lined by simple cuboidal to low columnar ciliated epithelial cells with sparse cellular organelles and prominent junctional complexes. Elongated single cilia arising from basal bodies in the apical cytoplasm were occasionally evident. The presence of such a neoplasm in a 4-month-old parrot is extremely unusual.