Rare but overlooked: choroidal metastasis as a late manifestation of colon cancer with review of literature

Choroidal metastasis is a rare but significant manifestation of systemic malignancies, most commonly originating from breast and lung cancers. Metastatic spread to the choroid from colorectal cancer (CRC) is exceedingly uncommon, with limited cases reported in the literature. However, it poses a significant diagnostic and therapeutic challenge when it occurs. 33 years old female with Adenocarcinoma of the colon T3N0M0 initially treated curatively, developed lung metastasis 18 months later. At 23 months post-diagnosis, she presented with blurred vision and severe pain. Ophthalmologic exam and imaging (OCT, ultrasonography, MRI) confirmed a choroidal lesion with retinal detatchment. A comprehensive review of available case reports and series of choroidal metastases originating from colorectal cancer was conducted. Data on patient demographics, symptoms, diagnostic modalities, treatment options, and outcomes were analyzed. Choroidal metastasis from CRC serves as a red flag for extensive disease and the most common presenting symptom is visual impairment, including blurred vision, scotomas, or diplopia. Clinically significant implications of this case are indication of advanced systemic spread, need for prompt multidisciplinary evaluation through clinical examination, fundoscopic findings, and imaging modalities such as optical coherence tomography (OCT), ultrasonography, and magnetic resonance imaging (MRI) andtreatment options which include external beam radiotherapy (EBRT), systemic chemotherapy, and targeted therapies to control ocular symptoms and improve visual function. Early recognition allows for integrated systemic and ocular care, and targeted local therapy can meaningfully improve visual outcomes.