A rare case of Lung adenocarcinoma complicated with leptomeningeal and brain parenchymal metastasis: case report and review of the literature.

Brain metastasis (BM) represents a severe and common complication of advanced lung cancer, which is clinically categorized into brain parenchymal metastasis (BPM) and leptomeningeal metastasis (LM), with LM being the predominant subtype of meningeal involvement. In clinical practice, the concurrent occurrence of both parenchymal brain and leptomeningeal metastases in a single patient remains rare. Here, we report a case of an epidermal growth factor receptor (EGFR)-mutant NSCLC patient with simultaneous BPM and LM, along with a review of current research progress on the treatment of BM. The patient had previously undergone surgery and targeted therapy, and subsequently developed bone metastases, LM and BPM. After receiving ventriculoperitoneal shunting, intrathecal chemotherapy via an Ommaya reservoir, and resection of the brain metastatic lesion, the patient's condition was effectively controlled. This case suggests that some EGFR-mutant NSCLC patients may still experience CNS progression during EGFR-tyrosine kinase inhibitor (TKI) therapy. Moreover, local therapy (surgery) combined with intrathecal chemotherapy may improve quality of life and prolong survival, thus representing a feasible treatment option.