Nivolumab (Opdivo) is an immune checkpoint inhibitor used in the treatment of multiple cancers including gastric adenocarcinoma. The diagnosis of antineoplastic therapy toxicity, such as nivolumab toxicity, occurs commonly in those receiving treatment with symptoms ranging from a rash to potentially death, which is an uncommon side effect. Patients who have cancer can develop the diagnosis of leptomeningeal carcinomatosis (LMC), which is considered rare, occurring in 2-4% of all cancers. The initial presentation with primarily neurological symptoms can occur in both diseases, however the prognosis and treatment varies greatly. In this case report, we discuss a patient with metastatic gastric adenocarcinoma reportedly in remission, who was initially being treated as having nivolumab toxicity, however 72 hours later he was found to have leptomeningeal carcinomatosis.
Keywords : leptomeningeal carcinomatosis, nivolumab, case report