A Complicated, Metastatic, Humeral Air Sac Cystadenocarcinoma in a Timneh African Grey Parrot (Psittacus erithacus timneh)

Abstract

A 9-year-old male timneh African grey parrot (Psittacus erithacus timneh) was presented because of inability to fly and suspected trauma. The owner also had observed dyspnea, with tail bobbing and open-beak breathing. On clinical examination, a hard, painful mass was palpable in the left proximal humerus and axillary area. Radiographs revealed a radiodense soft tissue mass of the left humerus with no bony involvement, multifocal opacities in lung and air sacs, and an enlarged spleen. An asymmetric, vascularized cyst was detected in the mass by ultrasound examination. Results of biopsy of the mass revealed multifocal cysts composed of unilayer isoprismatic cells laying in vascularized connective tissue. Because of the severity of clinical signs and the poor clinical condition, the bird was euthanatized. On postmortem examination, the findings were air sac cystadenocarcinoma involving the humeral air sac with metastases in the spleen and kidneys, atherosclerosis, pneumoconiosis, and mycotic granulomatous pneumonia and airsacculitis with isolation of Aspergillus niger.

The first occurrence of an avian-style respiratory infection in a non-avian dinosaur

“…Tumors of the avian respiratory tract are uncommon with fewer still reported within the air sacs. Occasional case reports exist in the literature with examples including air sac neoplasia of the sternum described in a quaker parrot 63 and of the humerus air sac of a salmon-crested cockatoo 64 and a Timneh African grey parrot 65 . These cases varied between no bone involvement to bone lysis and periosteal reaction.…”

Humeral air sac cystadenocarcinoma in a rainbow lorikeet (Trichoglossus moluccanus)

“…In this case, we report for the first time, the clinical and pathological manifestations of a cystadenocarcinoma arising from the air sac of the humerus in a rainbow lorikeet. Reports of air sac cystadenocarcinomas in the literature include neoplasia stemming from the humerus, femur, sternum and coelomic cavity . Air sac cystadenocarcinomas are most commonly reported in large psittaciformes, but reports exist in columbiformes, falconiformes and cuculiformes .…”

“…Air sac cystadenocarcinomas are most commonly reported in large psittaciformes, but reports exist in columbiformes, falconiformes and cuculiformes . The absence of smaller companion bird species in the literature is conspicuous, with three cases described in Moluccan cockatoos ( Cacatua moluccensis ), two case series' in cockatoos ( Eolophus roseicapilla and Cacatua galerita ) and a report of a complicated metastatic case in an African grey parrot ( Psittacus erithacus timneh ) . A single case report outlines an air sac adenocarcinoma in the sternum in a Quaker parrot ( Myiopsitta monachus ) that presented in respiratory distress …”

“…Signs in air sac cystadenocarcinomas include acute dyspnea, respiratory distress, sneezing, inappetance, inability to fly, change in voice, feather picking, a wing droop and generalised malaise . Respiratory signs are likely to be secondary to space occupying masses, pain, or gas exchange compromise.…”

“…The neoplastic process in this case displayed significant bone involvement that was predominantly characterised by a very granular, marked osteoproductivity, compared to any of the previously reported cases. The majority of masses in the previous cases involved soft tissue, some with minimal bone involvement radiographically . Each of the histopathological descriptions varies slightly but most describe neoplastic glands with columnar epithelium with uniform nuclei .…”