Branchial cysts in two Amazon parrots (Amazona species).

Abstract

A 37-year-old yellow-crowned Amazon parrot (Amazona ochrocephala) and a 20-year-old red-lored Amazon parrot (Amazona autumnalis) each presented with a large mass localized on the lateral neck. With the first bird, there was no evidence of signs of pain or discomfort, and the bird prehended and swallowed food normally. The second bird showed signs of mild upper-gastrointestinal discomfort. Results of an ultrasound examination and aspiration of the mass on each bird revealed a cystic structure. A computed tomography performed on the second bird revealed a large polycystic mass connected to the pharynx by a lateral tract. During surgical resection, both masses were found to originate from the subpharyngeal area. Based on topography and the histopathologic and immunohistochemical results, the masses were determined to be a second branchial cleft cyst for the first case and a second branchial pouch cyst for the second case. In addition, a carcinoma was present in situ within the epithelium of case 1, and the cyst in case 2 was secondarily infected. Branchial cysts are uncommonly diagnosed in veterinary and human medicine. These 2 cases are the first documented in parrots and appear similar to second branchial cysts reported in adult humans.