Pulmonary squamous cell carcinoma with duodenal metastasis: A case report of immunological hyperprogression.

Immune checkpoint inhibitors have significantly improved the treatment of non-small cell lung cancer by enhancing antitumor immune responses. However, not all patients achieve favorable outcomes. Immune hyperprogression is not uncommon in current adjuvant therapy, but the occurrence of metastatic tumors in the form of hyperprogression when the primary tumor is well controlled has not been reported. This case presents a patient who developed immune hyperprogression (duodenal metastasis) during the immune maintenance phase after surgery. This case underscores the potential for ectopic metastases and hyperprogression during immunotherapy. Clinicians are reminded of the importance of cautious immunotherapy, early identification of HPD, and personalized follow-up in the management of immunotherapy for non-small cell lung cancer.