Lung cancer spreading to the eye in four cats

Abstract

The objective of the research was to characterize the clinical, fluorescein angiographic, pathologic and microscopic features of feline pulmonary carcinoma with ocular metastasis that resulted in ischemic chorioretinopathy. Four cats with confirmed or presumed primary pulmonary neoplasia with posterior segment metastasis were studied. The medical records from four cats with a diagnosis of bronchogenic carcinoma and intraocular metastasis were reviewed. Physical and ophthalmic examinations and thoracic radiographs were performed in all cases, and fluorescein angiography was performed in two cases. Classification of the neoplasms was determined by fine‐needle aspiration and biopsies of peripheral metastatic lesions, and/or complete necropsies. All four cases had unilateral or bilateral blindness and ophthalmoscopic lesions characterized by a wedge‐shaped, tan discoloration in the tapetal fundus, variable but mild serous exudation under the retina, and profoundly attenuated retinal vasculature. Painful swelling and necrosis of the distal extremities and/or mass lesions in the appendicular musculature were also present. Clinical findings, along with microscopic findings from biopsy specimens or complete postmortem examination, documented widespread metastasis of variably differentiated, neoplastic, columnar epithelial cells presumed to be of bronchial origin. Tumor cells were predominately located within the systemic vasculature, consistent with classification of angioinvasive pulmonary carcinoma. Fluorescein angiographic and histopathologic findings in the affected globes suggested that the posterior segment lesions resulted from invasion and growth of neoplastic cells within the chorioretinal vasculature, resulting in secondary ischemic necrosis of the retina and choroid. Ischemic chorioretinopathy and necrosis of the distal extremities, associated with primary bronchogenic carcinoma, appear to be a unique neoplastic syndrome in the domestic cat.