Macroscopic, cytological and histological diagnosis of proventricular adenocarcinoma in a sulphur-crested cockatoo (Cacatua galerita).

An adult sulphur-crested cockatoo (Cacatua galerita) was unexpectedly found dead and was presented for post-mortem examination. Macroscopically, the proventricular wall was expanded by an infiltrative off-white mass, 10 mm in diameter, with secondary mucosal ulceration. Cytological examination of impression smears revealed a neoplastic epithelial cell population forming occasional well-defined acini with secretory product. Histologically, the neoplastic cells were predominantly arranged in acini and tubules, with fewer in small clusters, supported by a desmoplastic stroma. Neoplastic cells were polygonal, with mostly well-demarcated cell boundaries and a moderate amount of eosinophilic cytoplasm that was multifocally markedly distended by more intensely eosinophilic material. There was an increased nuclear-to-cytoplasmic ratio with moderately sized to large nuclei (approximately 15 μm diameter) with lightly to densely stippled chromatin and single or paired prominent basophilic nucleoli. The mitotic count was 19 in 10 high-power fields (2.37 mm), with scattered bizarre mitotic figures and atypia including moderate anisocytosis and anisokaryosis and moderate cellular and nuclear pleomorphism. There was frequent intratubular brightly eosinophilic proteinaceous material, which was Alcian blue and periodic acid‒Schiff positive. Proventricular lymphovascular invasion was detected, with metastases within the ventriculus and lungs. The macroscopic, cytological and histological appearance of the neoplasm was consistent with a proventricular adenocarcinoma.