Metastatic cholangiocellular carcinoma and renal adenocarcinoma in a golden eagle (Aquila chrysaetos)

A 33-year-old captive male golden eagle (Aquila chrysaetos) was presented for necropsy with a history of emaciation and depression. The liver was severely distorted by numerous, coalescent, poorly demarcated, white firm nodules. Upon microscopic examination, these masses were found to be infiltrative and were composed of anastomosing tubular structures lined by signet-ring cells piling up in a disorderly fashion. Ultrastructurally, neoplastic cells were characterized by abundant microvilli at their apical pole and by numerous junctional complexes on lateral cell membranes. Based on morphological criteria, this tumour was classified as a poorly differentiated cholangiocellular carcinoma. Metastases were found in kidneys, testes, lungs, air sacs, pericardium, pancreas, adrenals and meninges. Additionally, two (11 and 2 mm) beige nodules were found in the cranial portion of the left kidney. Histological examination revealed locally infiltrative compact masses composed of well-differentiated tubules lined by a tall columnar epithelium without microvilli. These tumours were diagnosed as renal tubular adenocarcinomas. This is believed to be the first case of two simultaneous malignancies reported in a bird of prey.