Abstract
Abstract: :
Purpose: Comparison of patterns of preoperative fluorescein angiography (FA) and histopathologic features of predominantly occult choroidal neovascular membranes (CNV) in patients with advanced AMD. Methods: 18 patients with advanced AMD were evaluated with FA followed by combined subretinal surgery and autologous transplantation of RPE. 18 excised CNV membranes studied by conventional histopathology and immunohistochemistry for CD31 (endothelial cell marker) to determine microvascular density (mvd; number of vessels/HPF x40) and pattern of angiogenesis, inflammatory infiltration and amount of matrix. Results: FA revealed predominantly occult membranes (either exclusively occult or with minimal classic parts) in all cases. 13/18 membranes exhibited signs of fibrosis, 7/18 lesions showed focal areas of neovascularization; retinal choroidal anastomoses (RCA) were detected in 6/18 and RPE detachment in 5/18 membranes. By histology, lesions exhibited 3 distinctive patterns: a) high and homogeneous mvd (>15 vessels/HPF), b) focal "angiogenic hotspots" in an otherweise matrix-rich, poorly vascularized membrane and c) minimal vascular scars. FA and histopathology: All 6 membranes classified as partially fibrotic by FA presented as minimal vascular scars in histopathology (mvdmax < 10), whereas the 2 cases with mvdmax> 15 corresponded to visible signs of neovascularization in FA images. The remaining 10 membranes were more heterogeneous by FA and were histologically characterized usually by a solitary angiogenic focus. RCAs were present in 21% of all membranes and seen in all groups. Conclusions: "Occult CNV" in FA is often used as a descriptive term for any neovascular lesion under the RPE, which is mostly poorly demarcated. Histologically these lesions show a spectrum of morphologic changes ranging from highly cellular fibrovascular tissue to mostly fibrotic scars.
Keywords: age-related macular degeneration • choroid: neovascularization • imaging methods (CT, FA, ICG, MRI, OCT, RTA, S