Malignant Melanoma of the Syrinx and Liver in an African Grey Parrot ( Psittacus erithacus erithacus).

A 20-year-old, female African grey parrot ( Psittacus erithacus erithacus) was examined because of ataxia and weakness. Radiographs were unremarkable, and results of a complete blood cell count revealed leukocytosis and heterophilia. Because of poor response to therapy with meloxicam, doxycycline, and enrofloxacin; deteriorating condition; and poor prognosis, the parrot was euthanatized. Postmortem examination revealed 2 dark red nodules in the liver. No grossly visible mass was observed in the syrinx. Histologic examination of the liver and syrinx revealed similar foci of round, oval, and polygonal cells exhibiting severe pleomorphism, with poorly demarcated cytoplasmic borders and moderate amounts of eosinophilic cytoplasm containing brown to black granules (melanin). The mitotic index was 15. The presence of melanin pigment is consistent with a diagnosis of melanoma at both sites. The multifocal distribution and intravascular invasion indicate metastasis; however, the site of origin was unknown. To our knowledge, this is the first recorded case of melanoma in an avian syrinx.