Histopathologic Findings in Postmortem Eyes after Photodynamic Therapy for Choroidal Neovascularization in Age-related Macular Degeneration: Report of Two Cases

Abstract

Background: To report the histopathologic findings after photodynamic therapy (PDT) in eyes obtained post-mortem with choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

Methods: Two eyes were obtained post-mortem from two patients with CNV secondary to AMD. Both of the patients had been treated with PDT. Serial sections through the posterior poles were obtained and stained with hematoxylin-eosin, periodic acid-Schiff, Masson trichrome or phosphotungstic acid hematoxylin (PTAH). Two-dimensional reconstructions were prepared and compared with fluorescein angiograms.

Results: The interval between PDT and death was 3 months and 17 months in each patient, respectively. Light microscopic examination showed CNV enveloped with retinal pigment epithelium (RPE) in both eyes. The average size of the CNV was 550 x 280 μm. One eye had combined (subRPE/subretinal) growth pattern CNV, and the other eye had both type I (subRPE) and combined growth pattern CNV. All specimens contained fibrous proliferation and patent vascular channels within the CNV and there was no thrombus formation within the vascular channels. No apparent abnormalities in the choroid were observed by light microscopy.

Conclusions: Although involution with fibrous tissue proliferation occurred, PDT did not result in permanent occlusion of the vascular channels in the CNV. Our findings indicate that PDT may accelerate involution of CNV, thus limiting its size and preserving photoreceptors.