What happened, in summary

A 61-year-old man with a long smoking history was diagnosed in March 2024 with lung adenocarcinoma showing neuroendocrine differentiation. By the time of his later admission, the cancer had spread widely, including to bone and multiple areas of the brain, skull, meninges, and pituitary region. Molecular testing did not identify common actionable alterations such as EGFR, ALK, ROS1, RET, MET, or HER2.

He first received sulfatinib and had some early improvement in the lung lesions, but the cancer later progressed. He then moved through several systemic treatments, including pemetrexed with cisplatin and bevacizumab, docetaxel with carboplatin, and anlotinib. In October 2024, worsening headache and facial weakness led to confirmation of multiple intracranial metastases. He received temozolomide, sintilimab, and bevacizumab.

Within days, he developed extreme thirst and very high urine output. Testing and pituitary imaging supported immune-related hypophysitis with diabetes insipidus, a serious immune-therapy complication. Sintilimab was stopped and high-dose steroids were given. His thirst, facial weakness, and urine output improved, and a family follow-up about 2 weeks after discharge reported that his urine output had returned to normal. The cancer itself remained advanced after several lines of treatment.