Retinal translocation and photodynamic therapy for age-related macular degeneration with classic choroidal neovascularization: a clinicopathologic case report

Histopathological findings in postmortem eyes after photodynamic therapy for choroidal neovascularisation in age-related macular degeneration: report of two cases

BACKGROUND

To report the histopathological findings after photodynamic therapy (PDT) in eyes obtained postmortem with choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD).

METHODS

Two eyes were obtained postmortem 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 haematoxylin-eosin, periodic acid-Schiff, Masson trichrome or phosphotungstic acid haematoxylin (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 that CNV enveloped with retinal pigment epithelium (RPE) in both eyes. The average size of the CNV was 550 x 280 microm. 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.

Clinicopathologic studies of eyes that were obtained postmortem from four patients who were enrolled in the submacular surgery trials: SST Report No. 16

PURPOSE

To compare the fundus photographic and fluorescein angiographic features with the histologic findings in eyes from patients enrolled in the Submacular Surgery Trials (SST).

DESIGN

Clinical trials with clinicopathologic correlation.

METHODS

Eyes that were obtained postmortem from patients who participated in the donor program were processed at the SST Pathology Center and examined histologically; the macular regions were reconstructed topographically with two-dimensional cartography. Fundus photographic and fluorescein angiographic features were correlated with the histopathologic and two-dimensional cartographic findings.

RESULTS

The eyes from two patients each from the SST Group N and B Trials were studied. The study eye of one patient that had been assigned randomly to observation contained a subretinal fibrovascular scar that corresponded to a histologic growth pattern of a thick, collagenized subretinal component combined with a subretinal pigment epithelium (subRPE) fibrovascular component. The study eye of the other patient who was assigned randomly to observation showed angiographic occult without classic choroidal neovascularization (CNV) that corresponded to subRPE CNV. The study eye of one patient who was assigned randomly to surgery showed an angiographic surgical defect without CNV and histologic retinal pigment epithelium (RPE)/photoreceptor atrophy that was associated with a thin layer of subRPE CNV. The study eye of the other patient who was assigned randomly to surgery showed an angiographic surgical defect with classic CNV that corresponded to histologic RPE/photoreceptor atrophy that was associated with subRPE fibrovascular tissue and subretinal CNV. Both surgical eyes contained linear breaks in Bruch's membrane that included chevron-shaped breaks.

CONCLUSION

Four SST study eyes that were examined postmortem contained CNV. The angiographic patterns and histologic features of the CNV support previous correlations of surgically excised CNV.

Basal deposits and drusen in eyes with age-related maculopathy: evidence for solid lipid particles

Neutral lipid, including esterified cholesterol, and apolipoproteins B and E are abundant in basal deposits and drusen of aged and age-related maculopathy (ARM) eyes. The principal component of basal linear deposit (BlinD), a specific ARM lesion, is membranous debris, which if actually derived from membranes cannot account for extracellular neutral lipid. We therefore used a lipid-preserving ultrastructural method to obtain improved images of membranous debris. Maculas from 44 human donors (71-96 yr) were preserved <7.5 hr after death. Blocks were post-fixed in 2% osmium or osmium-tannic acid-paraphenylenediamine (OTAP) to preserve neutral lipid for thin-section transmission electron microscopic (TEM) examination. Solid particles identified by OTAP were considered closest to the in vivo state of extracellular lipids. Micrographs were examined for intermediate forms, with greatest weight given to comparable images from different preparations of same or fellow eyes. Twenty eyes of older adults (12 with ARM including fellows treated with photodynamic and radiation therapies) had adequately preserved extracellular lipid. The exterior surface of membranous debris was thicker and more electron-dense than basal infoldings of retinal pigment epithelium (RPE) cells. By OTAP, individual membranous debris profiles were solid (diameters, 80-200 nm) and formed tracks across or aggregations within basal laminar deposits. Solid particles and/or pools of neutral lipid were visible in BlinD and drusen. When processed to preserve lipid, membranous debris resembles neither membranes of surrounding cells nor vesicles possessing aqueous interiors but rather solid particles. These results are consistent with recent evidence implicating lipoprotein particles of intra-ocular origin as a potential source of neutral lipids, including esterified cholesterol, in the specific lesions of ARM.

Choroidal neovascularization

PURPOSE

To review clinicopathologic findings of choroidal neovascularization (CNV) in a historical framework with emphasis on pathobiology and correlation with treatment.

DESIGN

Selective literature review combined with authors' experience.

RESULTS

Choroidal neovascularization represents a stereotypic, nonspecific response to a specific stimulus. Although CNV differs among patients, the general growth patterns are subretinal pigment epithelium (type 1), subretinal (type 2), or combined. Choroidal neovascularization occurs over time in dynamic stages of initiation, active and involutional. Treatments are now being designed based on modern understanding of CNV growth.

CONCLUSIONS

Progress continues to be made concerning understanding the pathobiology and treatment of CNV.

Clinicopathological findings of choroidal neovascularisation following verteporfin photodynamic therapy

AIMS

To report the clinicopathologic findings of surgically excised choroidal neovascularisation (CNV) three days after verteporfin photodynamic therapy (PDT).

METHODS

In three patients (three eyes) with age related macular degeneration, the CNV was surgically removed three days after PDT. The CNV specimens were examined by light microscopy.

RESULTS

The patients had subfoveal classic CNV. Fluorescein angiography revealed non-perfusion of the CNV after PDT and before surgery in all eyes. The light microscopy of the CNV membranes showed swollen and damaged endothelium. Thrombus formation or vascular occlusion in the CNV vessels was not detected.

CONCLUSION

PDT did not cause a thrombosis of the vessels within the CNV three days after PDT. Severe endothelial damage of the CNV was observed and is likely a primary effect of PDT. Non-perfusion of the CNV at this stage is possibly secondary to occlusion at a deeper level, namely the underlying feeding choroid.

Histological findings of a surgically excised myopic choroidal neovascular membrane after photodynamic therapy. A case report

BACKGROUND

The authors describe a myopic choroidal neovascular membrane excised 4 months after photodynamic therapy (PDT).

METHODS

A 68-year-old woman with classic choroidal neovascularization (CNV) due to pathologic myopia underwent PDT with verteporfin in the left eye. Four months after treatment a full-thickness macular hole was diagnosed in the same eye and the patient underwent vitrectomy with submacular membranectomy. The subfoveal membrane was studied by light microscopy and immunohistochemical techniques.

RESULTS

Light microscopy showed a thin fibrovascular membrane covered by residual retinal pigment epithelium. The membrane contained homogeneous matrix with small collagen bundles, fibroblasts and small blood vessels. The distribution of blood vessels was nonuniform: extravasated red blood cells, macrophages and other inflammatory elements were not present in the fibrous matrix. Endothelial cells were highlighted by CD34 immunostaining and did not show any significant alteration. There was no evidence of inflammatory cells or thrombosis inside vascular lumina.

CONCLUSIONS

Histologic examination of the neovascular membrane showed features similar to those of surgically excised myopic CNV without PDT treatment. Our findings suggest that PDT-induced occlusion is temporary. Fluorescein leakage from CNV after a single PDT treatment can be considered as an sign of blood vessel regrowth or recanalization indicating that multiple treatments are necessary.