BACKGROUND: Cytoreductive surgery and intraoperative, intraperitoneal hyperthermic chemoperfusion (HIPEC) is increasingly used to treat peritoneal surface metastases. We describe a fatal case of cerebral edema in a patient with appendiceal carcinoma and an underlying seizure disorder who underwent cytoreductive surgery and HIPEC. CASE PRESENTATION: A case of fatal postoperative cerebral edema is presented in a patient with an underlying seizure disorder and recurrent mucinous adenocarcinoma of the appendix. The patient was treated with cytoreductive surgery and intraoperative intraperitoneal hyperthermic chemoperfusion. The details and implications of this complication are discussed. CONCLUSION: The recognition of this potential complication is important for physicians performing cytoreductive surgery and HIPEC. Special caution should be taken when patients with seizure disorders are being considered for this treatment.