What happened, in summary

A 79-year-old woman underwent thoracoscopic left upper lobectomy with lymph-node dissection for Stage II cancer of the left upper lung. Brain MRI before surgery showed no metastases, but it did identify an incidental meningioma in the left frontal region. Six months later, follow-up MRI showed a new ring-enhancing lesion with surrounding swelling next to the meningioma. A brain metastasis was suspected. She underwent a frontotemporal craniotomy, and surgeons removed the cystic metastatic tumor together with the adjacent meningioma and involved dura. Pathology confirmed a low-grade meningioma and a separate metastatic tumor whose findings matched the prior lung cancer. The metastatic tumor partly infiltrated the meningioma tissue, an unusual pattern of spread. Her postoperative recovery was uncomplicated, and she was discharged on day 13. She declined radiochemotherapy after the brain surgery. The confirmed brain metastasis meant the lung cancer had progressed to Stage IV. Imaging also showed a 15-mm nodule in the right lung that was considered suspicious.