Case Presentation: A 27-year-old man with metastatic gastroesophageal junction adenocarcinoma presents with five weeks of worsening thigh pain. Labs are notable for CSF with malignant cells. Brain and spine MRI reveal diffuse leptomeningeal carcinomatosis. His course is complicated by severe pain that requires increasing doses of opioids. During his hospitalization, the patient develops worsening headaches, [...]