PT - JOURNAL ARTICLE AU - A. Dasgupta AU - F.Y. Moraes AU - S. Rawal AU - P. Diamandis AU - D.B. Shultz TI - Focal Leptomeningeal Disease with Perivascular Invasion in <em>EGFR</em>-Mutant Non-Small-Cell Lung Cancer AID - 10.3174/ajnr.A6640 DP - 2020 Jul 02 TA - American Journal of Neuroradiology 4099 - http://www.ajnr.org/content/early/2020/07/02/ajnr.A6640.short 4100 - http://www.ajnr.org/content/early/2020/07/02/ajnr.A6640.full AB - SUMMARY: We report a previously undescribed pattern of brain metastases in patients with epidermal growth factor receptor–mutated non-small-cell lung cancer treated with tyrosine kinase inhibitors and radiation therapy. These highly distinct lesions appear to spread focally within the leptomeninges, with invasion along the perivascular spaces (FLIP). The survival of patients with FLIP was significantly better compared with patients with classic leptomeningeal disease (median survival, 21 versus 3 months; P = .003). It is unclear whether this pattern of growth is unique to epidermal growth factor receptor–mutated non-small-cell lung cancer.EGFRmepidermal growth factor receptor–mutatedcLMDclassic leptomeningeal diseaseFLIPfocal leptomeningeal involvement with invasion of the perivascular spaceNSCLCnon-small-cell lung cancerTKItyrosine kinase inhibitorsWBRTwhole-brain radiation