Thoracic teratoma in a white Pekin duck (Anas platyrhinchos domesticus)

Intracoelomic Teratoma in an Eclectus Parrot (Eclectus roratus)

A 26-year-old, male eclectus parrot (Eclectus roratus) was presented to its primary care veterinarian for a 10-day history of increased respiratory effort, lethargy, and a single episode of regurgitation. Hepatomegaly, proventricular enlargement, cranial displacement of the ventriculus, and coelomic effusion were suspected based on a 1-view radiographic image, and the patient was referred for further evaluation. On presentation to the referral veterinary hospital, a distended coelom and dyspnea with abnormal respiratory sounds were abnormalities noted upon physical examination of the patient. The bird was hospitalized for supportive care, and diagnostic tests were performed. Initial radiographic images at the referral hospital revealed a large intracoelomic mass. A computed tomographic scan was performed; however, the origin of the mass could not be determined. A fine-needle aspirate and cytologic evaluation of the intracoelomic mass revealed a neoplastic process but no specific tissue type. Two days after presentation to the referral hospital, an exploratory coeliotomy to surgically resect the mass was attempted. The mass occupied most of the coelomic cavity, with multiple adhesions to internal organs. The mass was successfully resected; however, the patient destabilized and died despite resuscitation efforts. Histopathologic examination of submitted tissue from the mass with immunohistochemistry revealed mixed populations of neoplastic cells differentiated from 3 primordial germinal layers, confirming the diagnosis of teratoma. Teratomas appear to be a rare tumor in avian species but should be included in a list of differential disease diagnoses for abnormal tissue masses of unknown origin. Only 2 cases of teratomas have, to our knowledge, been reported in psittacine species.

Brain teratoma in a free-ranging mallard (Anas platyrhynchos) ˗ case report

ABSTRACT Teratoma is a rare neoplasia with differentiation in two or three germ cell lines. Intracranial teratoma in birds has rarely been reported, especially affecting the brain. This is the first report of a brain teratoma in a mallard with neurological clinical signs. The neoplasm was characterized as a mature brain teratoma, extending from the cerebellum to the brainstem, and with one nodule in the cortex.

Recurrent Subcutaneous Teratoma in an Adult Red-crowned Amazon Parrot (Amazona viridigenalis)

An approximately 42-year-old, wild-caught, red-crowned Amazon parrot (Amazona viridigenalis) was evaluated for a subcutaneous mass to the right of the keel. Cytologic examination of a fine needle aspirate of the mass were suggestive of granulomatous inflammation. The mass was surgically excised, and the parrot was treated with oral nonsteroidal anti-inflammatory drugs. Histologically, the mass was diagnosed as a teratoma with stratified squamous epithelial and neuroectodermal components. Tumor cells extended to surgical margins. Two years later, the neoplasm recurred, with regrowth of only the neuroectodermal component. The neoplasm was again removed surgically, but it recurred again 14 months later, necessitating a third surgery. Histopathologic examination confirmed recurrence of the original neoplasm in both instances, with incomplete margins on both excisions.

COELOMIC TERATOMA IN A BLUE-AND-YELLOW MACAW (ARA ARARAUNA)

A 2-mo-old, female blue-and-yellow macaw (Ara ararauna) presented with severe abdominal distension, pain, and respiratory distress. Ultrasonographic examination detected a heterogeneous mass with multiple anechoic areas, compatible with a multilocular cyst, occupying most of the coelomic cavity. Postmortem examination revealed a mass of 12.0 × 8.5 × 5.0 cm, which had an irregular surface and was connected by a pedicle to the ileum. This mass compressed and displaced the liver, proventriculus, gizzard, and intestines cranially to the left. The cut surface was lobulated, gray-white, mildly firm or soft, and was interspersed with multiple cysts filled with viscous and opaque liquid. Microscopically, it was composed of well- differentiated embryonic tissues from the endoderm, mesoderm, and ectoderm; therefore, it was diagnosed as a mature teratoma, which was theorized to have originated from Meckel's diverticulum. This study is the first, to the authors' knowledge to report a case of a teratoma in a blue-and-yellow macaw.

"TERATOCARCINOMATOSIS" IN AN EMU (DROMAIUS NOVAEHOLLANDIAE)

An adult female emu (Dromaius novaehollandiae) with no previous abnormal clinical signs was found dead in its stall. A postmortem examination revealed carcinomatosis of unknown origin. Histopathology identified the masses as teratomas with malignant transformation by the presence of poorly differentiated tissue and dissemination throughout the coelomic cavity. We propose a new term, "teratocarcinomatosis," for this finding. This is the first case of a reproductive tumor described in an emu and the first case of such marked spread of malignant teratomas in a bird.

Extragonadal teratoma in a domestic turkey (Meleagris gallopavo domestica)

This is the first report of a primary, spontaneous and, most probably, congenital teratoma in a domestic turkey, localized in front of the left eyeball. The unique localization allowed surgical excision of the tumour. The histopathological examination revealed that the tumour included structures derived from all three germ cell layers: ectoderm, mesoderm and endoderm (e.g. cartilaginous, osseous, haematopoietic, fibrous, nervous, glandular, squamous epithelial and smooth muscle tissues). The presence of epithelial cells as well as smooth muscle cells was confirmed using anti-cytokeratin and anti-desmin antibodies, respectively. The proliferative activity of the tumour cells was confirmed using proliferating cell nuclear antigen immunostaining. The other cases of teratoma in wild and domestic birds are reviewed briefly.