RESUMO
BACKGROUND: Systemic chemotherapy combined with steroids used as prophylactic antiemetics have been reported to induce immunosuppression. Further, herpes simplex virus-1 (HSV-1) infection has been reported to occur in patients with small cell carcinomas after chemoradiotherapy that includes brain irradiation. Here, we report a case of HSV-1 encephalitis that occurred in a patient undergoing chemoradiotherapy for advanced esophageal cancer. CASE PRESENTATION: A 77-year-old woman received chemoradiotherapy (5-fluorouracil, 700 mg/m(2); cisplatin, 70 mg/m(2); and radiotherapy, 60 Gy in total) for stage III esophageal cancer. The total radiation dose was administered concurrently with the first two courses of chemotherapy, together with dexamethasone as a prophylactic antiemetic. Two days before completion of the fourth course of chemotherapy, the patient developed acute neurological symptoms of disorientation, clouding of consciousness, and fever. T2-weighted magnetic resonance imaging showed a high intensity area in the bilateral temporal lobes and insular cortex. Furthermore, DNA PCR testing of cerebrospinal fluid showed clear positivity for HSV-1 DNA, and the patient was diagnosed with herpetic encephalitis. Intravenous administration of acyclovir for 3 weeks led to gradual improvement of consciousness, and the patient was able to respond to verbal cues. CONCLUSION: In advanced esophageal cancer patients, standard treatment involves chemoradiotherapy and surgery. However, primary infection with or reactivation of endogenous latent HSV-1 in the brain cortex during chemoradiotherapy combined with administration of a steroid may compromise the benefits of treatment.