GATA-3 biomarker as a confounding factor in a patient with intraocular metastasis from squamous cell carcinoma of the lung.

Metastatic tumours to the retina are rare and are mainly found in the uvea (choroid, iris, or ciliary body). Despite their rarity, they pose a diagnostic challenge due to their diverse origins and subtle manifestations. This study examines the clinical characteristics and diagnostic challenges of retinal metastases through a literature review and a case involving a 74-year-old male with a painful blind left eye. Initially, the condition was diagnosed as transitional cell carcinoma retinal metastasis based on GATA-3 biomarker expression. Despite multiple examinations, including by retinologists, the finding was incidental, identified by the pathologist without prior suspicion. Through the analysis of clinical and radiological findings, we emphasize the importance of recognizing ocular symptoms as potential indicators of systemic malignancies, particularly in atypical presentations. We highlight the utility of immunohistochemical markers and radiological imaging in diagnosis and treatment guidance. Our findings stress the need for interdisciplinary collaboration between ophthalmologists, oncologists, and pathologists in the management of retinal metastases and thorough anatomical pathology evaluation.