Case Report: Rare Peripheral Neuropathy With Abdominal Wall Allodynia in Extensive-Stage Small-Cell Lung Cancer Treated Using Durvalumab.

Immune checkpoint inhibitors (ICIs), such as PD-1/PD-L1 inhibitors, have revolutionized the treatment of extensive-stage small-cell lung cancer (ES-SCLC). Chemotherapy combined with PD-1 or PD-L1 inhibitors has become the standard first-line treatment for ES-SCLC. However, with the broad application of immunotherapy, adverse events associated with this therapy have been increasingly reported by clinicians. The identification of atypical and specific manifestations of immune-related adverse events (irAEs) requires accumulated experience on the part of clinicians. In this article, we report the case of a patient over 50 years of age who was initially diagnosed with ES-SCLC. Clinical symptoms mainly manifested as allodynia of the abdominal wall following PD-L1 inhibition immunotherapy. This symptom progressed with continued immunotherapy and resolved after cessation of immunization and treatment with prednisone. A peripheral neuropathy antibody test revealed anti-GM4 IgG antibody positivity. On the basis of the patient's clinical manifestations and medication history described above, a diagnosis of immune-related peripheral neuropathy was made. In this case, the irAE severely hindered the treatment process and impaired the patient's quality of life. Through this case report and a review of the literature, we aim to explore how to timely and accurately identify irAEs in immunotherapy, especially nonspecific irAEs, and provide timely treatment to improve patient quality of life and survival and immunotherapy precision and safety.