Abstract
We report a rare case of small-cell lung cancer (SCLC) detected 14 months after the initial manifestation of brain metastases. A 71-year-old man presented with neurological symptoms that led to the resection of brain neuroendocrine carcinoma (NEC). Despite extensive imaging, no primary tumor was detected during the initial visit. Fourteen months later, a lung nodule appeared in the emphysematous bullae in the left upper lobe, which was confirmed as SCLC. Chemotherapy plus durvalumab was administered to control the tumor. This case highlights the diagnostic challenges of occult SCLC and emphasizes that brain NEC should be carefully followed-up, particularly in patients with emphysema.