Herpes simplex virus-1 encephalitis induced by chemoradiotherapy and steroids in an esophageal cancer patient: a case report

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.

A 77-year-old woman received chemoradiotherapy (5-fluorouracil, 700 mg/m²; cisplatin, 70 mg/m²; 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.

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.