A unilateral, malformed gnathotheca in a green-winged macaw (Ara chloropterus) was managed for 16 mo with periodic beak trims. Biopsy of the affected beak did not identify an underlying cause; however, at postmortem examination, a densely cellular neoplasm invaded the mandible from the beak, dissecting and effacing the cortex and trabecular bone and inciting periosteal proliferation. There was no evidence of metastasis. Neoplastic cells were strongly immunopositive for cytokeratin AE1/AE3, consistent with squamous cell carcinoma (SCC). A black-headed caique (Pionites melanocephalus) was presented with a similar clinical history, timeline, and gross appearance. Biopsy of the mandibular portion of the lesion resulted in a diagnosis of SCC. Medical management with toceranib at a palliative dose resulted in adverse side effects and was discontinued. Early diagnosis of mandibular SCC may allow for early intervention and development of treatment modalities. Our 2 cases suggest that the mandibular bone, not the beak, may be a preferred biopsy site in the diagnosis of mandibular SCC in psittacines.

中文翻译：

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2 psittacines中的下颌鳞状细胞癌。

在绿翅金刚鹦鹉（Ara chloropterus）中，单侧畸形的猕猴桃被管理了16个月，并进行了定期的喙修整。受影响的喙的活检未发现根本原因；然而，在死后检查中，一个密集的细胞瘤从喙中侵入下颌骨，使皮层和小梁骨解剖并消失，并刺激骨膜增生。没有转移的证据。肿瘤细胞对细胞角蛋白AE1 / AE3具有强免疫阳性，与鳞状细胞癌（SCC）一致。出现了黑头轻舟（Pionites melanocephalus），具有相似的临床病史，时间表和总体外观。对病变的下颌部分进行活检可诊断为SCC。姑息性托拉尼布的药物治疗导致不良副作用，因此停用。下颌SCC的早期诊断可允许早期干预和发展治疗方式。我们的2例病例表明，下颌骨而非喙可能是诊断psittacines下颌SCC的首选活检部位。