Fig. 1.

Distinct invasion patterns in human brain metastases. Top row: example of well-demarcated invasion (patient 5, NSCLC, Supplemental Table S1): (Aa) H&E slide (magnification ×1.25); (Ab) invasion front of well-demarcated brain metastasis (magnification × 400); (Ac) macroscopic sample of well-demarcated brain metastasis; (Ad) MRI contrast-enhanced T1-weighted sequence sample of well-demarcated brain metastasis. Middle row: example of vascular co-option (patient 13, melanoma, Supplemental Table S1): (Ba) H&E slide (magnification × 1.25); (Bb) CD34 immunohistochemistry of vascular co-option (magnification × 400); (Bc) macroscopic sample of brain metastasis growing via vascular co-option; (Bd) MRI contrast-enhanced T1-weighted sequence sample of brain metastasis growing via vascular co-option. Bottom row: example of diffuse invasion (patient 2, SCLC, Supplemental Table S1): (Ca) H&E of brain metastasis (magnification × 1.25); (Cb) CD18 cytokeratin staining showing diffusely infiltrating tumor cells; (Cc) macroscopic sample of diffuse infiltrating brain metastasis; (Cd) MRI contrast-enhanced T1-weighted sequence sample of diffuse infiltrating brain metastasis. Color figures available from authors upon request.