Fig 4. Macroscopic and pathologic findings of recurring aneurysm 3 months after coil embolization. A, Macroscopic photograph showing incomplete neck closure. B, Low magnification of overview of axial aneurysm section revealing a recurring lesion extending from the corner of the neck to the body of the aneurysm (arrow). These crescentic spaces are lined by smooth muscle (SM) –actin⁺ cells (C) and covered with NOS⁺ endothelial cells (D). E, Higher magnification showing the same layer of SM -actin⁺ cells covered with NOS⁺ endothelial cells. F, Atrophy of the aneurysmal wall in the occluded zone. G, No atrophy of the aneurysmal wall in the recurring zone. Sections are hematoxylin-counterstained (scale bar: 1000 µm for B; 200 µm for C–G; 40 µm for insets in C and D).