Listeria monocytogenes meningitis after pembrolizumab-based chemoradiotherapy for cervical cancer: A case report

Listeria monocytogenes is a major cause of invasive infections in individuals with impaired cell-mediated immunity. Recently, the combination of pembrolizumab with concurrent chemoradiotherapy has been established as the standard treatment for high-risk, locally advanced cervical cancer. Nevertheless, characterization of severe infections that occur during this treatment regimen remains inadequate. Herein, we report a case of L. monocytogenes meningitis that occurred during pembrolizumab-based chemoradiotherapy for cervical cancer. A 45-year-old woman with no underlying medical conditions was diagnosed with p16-positive cervical squamous cell carcinoma, involving the pelvic, para-aortic and left supraclavicular lymph nodes. The patient received concurrent chemoradiotherapy with weekly cisplatin and pembrolizumab every 3 weeks. On day 44, after receiving 50.4 Gy of external beam radiotherapy, she developed febrile neutropenia with a temperature of 40.1 °C, white blood cell count of 600/μL, absolute neutrophil count of 408/μL, and worsening diarrhea. She was treated with cefepime, and blood and urine cultures were negative. Immune-related adverse events,including endocrine disorders, were considered unlikely. After clinical improvement, she completed the concurrent chemoradiotherapy phase. On day 73, the patient presented with headache, nausea, and vomiting. Cerebrospinal fluid examination revealed neutrophilic pleocytosis, elevated protein levels, and hypoglycorrhachia. Blood and cerebrospinal fluid cultures yielded L. monocytogenes. She was treated with ampicillin and gentamicin for 3 weeks and recovered. Thus, fever during pembrolizumab-based chemoradiotherapy should not be solely attributed to immune-related adverse events. Severe infections, including Listeria meningitis, should be considered when fever or neurological symptoms occur, particularly in patients with myelosuppression, immune dysregulation, or gastrointestinal toxicity.