Posterior Scleritis as a Paraneoplastic Syndrome in Colon Cancer: A Case Report

This study presents a rare case of unilateral posterior scleritis as an ophthalmic manifestation of a paraneoplastic syndrome. A 61-year-old man presented to our department complaining of gradual worsening of vision in his left eye. Visual acuity was 10/10 and 3/10 in his right and left eye, respectively. He also mentioned that he experienced posterior ocular pain while sleeping at night, but was otherwise asymptomatic. His past ophthalmic and medical history were clear. A thorough clinical, imaging (fundus photography, optical coherence tomography, fluorescein angiography, and B-scan), and laboratory investigation was carried out. A diagnosis of posterior scleritis was made, but no obvious cause or underlying disease was identified even after a thorough systematic assessment. Regular follow-up within the next few months did not reveal any further pathological findings. Finally, 6 months after the initial presentation, the patient was diagnosed with colon cancer. Posterior scleritis can present as an ophthalmic manifestation of a paraneoplastic syndrome in patients with an underlying malignancy, even months before the presentation of systemic symptoms and diagnosis of the underlying disease. In conclusion, in patients (especially older adults) with posterior scleritis, the possibility of a malignant neoplasia must not be ignored or underestimated (paraneoplastic syndrome).