Visual Symptoms as the First Clue: A Case of CLOCCs Syndrome with Radiological Correlation

Cytotoxic lesions of the corpus callosum (CLOCCs) are hyperintense lesions that occur in the splenium of the corpus callosum due to various causes such as infections, metabolic disorders, or drug exposure. A 27-year-old female healthcare worker presented with blurred vision, visual trails, and decreased attention following an influenza infection treated with oseltamivir. Brain MRI demonstrated a well-defined splenial lesion with restricted diffusion, consistent with CLOCCs. The patient’s symptoms resolved within four days, and follow-up MRI at one month showed complete resolution. This case demonstrates that CLOCCs may manifest with nonspecific visual symptoms following viral infections, highlighting the need to recognize their imaging characteristics and to distinguish them from demyelinating or ischemic lesions to guide proper management.