Facial nerve injury immune‑related adverse events associated with adjuvant pembrolizumab therapy: A case report

Abstract

Anti‑PD‑1 and PD‑L1 inhibitors are associated with several adverse events, including a spectrum of immune‑related adverse effects (irAEs). Neurologic irAEs are uncommon occurrences with varied presentations. The present study presents a case of facial nerve injury irAEs associated with adjuvant pembrolizumab therapy (Keytruda^®), which exhibited unusual presentations. A 44‑year‑old male patient with extensive‑stage small‑cell lung cancer (ES‑SCLC) was treated with a 6‑cycle etoposide and cisplatin (EP) regimen followed by 200 mg pembrolizumab (Keytruda^®) intravenously once every 3 weeks. Magnetic resonance imaging (MRI) imaging of the brain revealed that there were abnormal enhancement areas in the left pontine crus, with clear boundaries. The patient terminated the use of pembrolizumab; however, EP chemotherapy continued and he was treated with high‑dose hormone therapy with the resolution of neurological symptoms. A total of 40 mg methylprednisolone was administered for 5 days and the patient was then administered oral prednisone tablets (25 mg). After 1 week, the facial symptoms were significantly alleviated. Following hormone therapy, the re‑examination of head MRI revealed that the lesion had shrunk and the symptoms had improved. The patient remains disease‑free. Facial nerve injury of neurological irAEs is uncommon adverse events in the context of PD‑1 inhibitor therapy. The neurotoxicity caused by immune checkpoint inhibitors (ICIs) should be a cause of concern. The early recognition of neurological irAEs is critical for the initiation of specific anti‑inflammatory agents for the prevention of such events. These events are usually alleviated with hormone therapy, which can distinguish metastatic tumors from neuropathy.