Oxaliplatin-induced posterior reversible encephalopathy syndrome with isolated involvement of pons

Isolated pontine lesion can be caused by the posterior reversible encephalopathy syndrome (PRES). It does occur in the normotensive patient who is treated with oxaliplatin. We reported a case of 81-year-old Chinese man with metastatic colorectal carcinoma who was initially treated with capecitabine. No significant adverse effects were noted. However, the response to the treatment was poor. Subsequently, Xelox was given. He developed transient altered mental status. Oxaliplatin was thought to be the causative agent and was withheld. Magnetic resonance imaging brain revealed vasogenic edema in the pons that was reversible after 2 weeks, as well as complete resolution of clinical symptoms. Early identification of the reversible cause of isolated pontine lesion, such as chemo, triggered PRES is crucial to facilitate prompt treatment by removing the offending agent or reducing the dose.