Zenaida de la Cruz

Idiopathic Epiretinal Membranes: Ultrastructural Characteristics and Clinicopathologic Correlation+

Current theories of idiopathic epiretinal membrane (ERM) pathogenesis, based mainly on clinical and autopsy studies, emphasize a glial tissue origin. The clinical and ultrastructural features of 101 cases of idiopathic ERMs removed from the macular area during vitrectomy were studied. The predominant cell type was retinal pigment epithelium (RPE) in 51 cases, fibrous astrocytes in 29 cases, fibrocytes in 14 cases, and myofibroblasts in 7 cases. Features of myofibroblastic differentiation were present in 64 cases. Myofibrocytes were more common in younger patients with shorter duration of symptoms. Fibrous astrocytes were more common in females. The high incidence of RPE cells in this series raises new questions regarding the pathogenesis of idiopathic ERMs.

Clinicopathologic Correlation of a Macular Hole Treated by Cortical Vitreous Peeling and Gas Tamponade

PURPOSE To study the histopathology of a stage III macular hole that had been treated by vitrectomy with cortical vitreous and epicortical vitreous membrane peeling and gas tamponade. METHODS The light and electron microscopic features of a treated macular hole were studied. RESULTS A 16-microns-wide break was present in the external limiting membrane. This was sealed by Müller cell processes. Photoreceptors adjacent to the healed defect appeared normal. No cystoid macular edema was present. CONCLUSION Cortical vitreous peeling and gas tamponade can allow the macular hole to settle and the edges to re-approximate. The residual defect can be sealed by Müller cells.

Autosomal-dominant Fundus Flavimaculatus: Clinicopathologic Correlation

The authors report the first clinicopathologic study of autosomal-dominant fundus flavimaculatus with late-onset atrophic macular degeneration in a 62-year-old man. Results of histopathologic examination disclosed the retinal pigment epithelium (RPE) to be distended by a periodic acid-Schiff (PAS)-positive, acid mucopolysaccharide-negative material. Transmission electron microscopy showed marked accumulation of lipofuscin and melanolipofuscin granules within the RPE. The different modes of genetic transmission and ultrastructural heterogeneity suggest that fundus flavimaculatus is a clinical syndrome representing several genetically and mechanistically distinct disorders whose common end-stage is a topographically similar accumulation of lipofuscin.

Ultrastructural Studies of Vitreomacular Traction Syndrome

We performed electron microscopic studies on seven specimens removed from the posterior retina at the time of vitrectomy for vitreomacular traction syndrome. Fibrous astrocytes were the predominant cell type in all cases. Fibrocytes were present in two cases and myofibrocytes were seen in three cases. Additional cellular and extracellular features included fragments of internal limiting membrane in six cases, old collagen in all cases, new collagen in one case, occasional macrophages in four cases, and fibrous astrocytes with myofibroblastic differentiation in one case.

Histopathology of Tissue Removed During Vitrectomy for Impending Idiopathic Macular Holes

Vitrectomy may prevent the progression of an impending macular hole by removing the layer of cortical vitreous from the posterior retina. To determine the nature of the cortical vitreous tissue, we identified and removed from the surface of the posterior retina a thin sheet of what appeared to be posterior cortical vitreous in 29 patients undergoing vitrectomy for an impending macular hole. In seven patients, the tissue was isolated for transmission electron microscopic study. Millipore filter specimens of the vitreous aspirates from all of the patients were studied by light microscopy. Vitreous condensates were present in all 29 specimens, fibrocellular membrane fragments were present in three, and fragments of internal limiting membrane were present in four. A collagen matrix was present in each of the seven specimens studied by electron microscopy, and in every specimen, the collagens diameter was consistent with indigenous vitreous collagen. These findings confirm the presence of an acellular tissue layer on the posterior retina in eyes with an impending macular hole and indicate that it is usually indigenous vitreous collagen.

A Clinicopathologic Study of the Eyes in Familial Adenomatous Polyposis by Extracolonic Manifestations (Gardner's Syndrome)

The eyes of a 51-year-old woman with familial adenomatous polyposis and extracolonic manifestations (Gardners syndrome) were obtained postmortem and studied by light microscopy and by transmission and scanning electron microscopy. We found a generalized abnormality in melanogenesis of the retinal pigment epithelium and at least three types of pigmented lesions. The histologic findings in one type of lesion were consistent with congenital hypertrophy of the retinal pigment epithelium or benign pigmented nevus of the retinal pigment epithelium. The other two types of lesion were most consistent with hamartomatous malformations of the retinal pigment epithelium featuring cellular hypertrophy, hyperplasia, and rarely retinal invasion and formation of a minute mushroom-shaped tumor. These histopathologic findings indicate a generalized effect of the familial adenomatous polyposis gene on the retinal pigment epithelium. This oncogene, which is responsible for tumor formation in the gastrointestinal tract, soft tissues, bone, and other locations in patients with familial adenomatous polyposis, also leads to a generalized defect in melanogenesis and focal lesions of the retinal pigment epithelium.

Clinicopathologic Correlation of an Untreated Macular Hole and a Macular Hole Treated by Vitrectomy, Transforming Growth Factor-β2, and Gas Tamponade

PURPOSE To study the clinicopathologic features of an untreated macular hole in the right eye and a macular hole in the left eye treated by vitrectomy, application of transforming growth factor-beta 2, and gas tamponade. METHODS The patient, a 73-year-old man with bilateral macular holes, was studied clinically before and after surgical treatment of the macular hole in his left eye. The patients eyes were obtained postmortem and serially step-sectioned through the macula and optic nerve head for electron microscopy. RESULTS Examination of 1-micron thick plastic-embedded sections through the macula of the right eye disclosed a 0.6-mm macular hole with rounded gliotic margins, a thin epiretinal membrane, and parafoveal cystic changes. Examination of 1-micron thick plastic-embedded sections through the macula of the left eye disclosed a 0.25-mm defect in the fovea, which was bridged by glial cells. The glial cells were continuous with a thin hypocellular epiretinal membrane without contraction features on both sides of the defect. The ultrastructural features of the glial cells were consistent with Mueller cells. CONCLUSIONS Treatment of a macular hole with vitrectomy, transforming growth factor-beta 2, and gas tamponade was followed by complete closure of the macular hole by Mueller cell proliferation.

Clinicopathologic studies of age-related macular degeneration with classic subfoveal choroidal neovascularization treated with photodynamic therapy.

Background Photodynamic therapy (PDT) is a relatively new modality that is currently under clinical and experimental evaluation for treatment of subfoveal choroidal neovascularization (CNV). The authors report the case of an 82-year-old woman who underwent verteporfin-mediated PDT for classic subfoveal CNV. Fluorescein angiography performed 2 weeks after treatment disclosed reduction of the initial area of neovascularization and leakage by approximately 60%. Three weeks after PDT, however, the area of leakage was almost the same size as that before treatment. The patient underwent submacular membranectomy almost 4 weeks after treatment. The authors describe the ultrastructural vascular changes after PDT and a clinicopathologic study of classic CNV. Methods The submacular membrane was studied by light and electron microscopy and immunohistochemical techniques. Results Ultrastructural examination of the peripheral vessels showed evidence of endothelial cell degeneration with platelet aggregation and thrombus formation. Occasional occluded vessels were surrounded by macrophages, a phenomenon previously reported to describe the process of resorption of such blood vessels. The vessels in the center of the membrane were unremarkable. Conclusion Photodynamic therapy causes endothelial cell damage, thrombus formation, and vascular occlusion of classic CNV in age-related macular degeneration.

CLINICOPATHOLOGIC CORRELATION OF RECURRENT EPIRETINAL MEMBRANES AFTER PREVIOUS SURGICAL REMOVAL

Recurrent epiretinal membranes (ERMs) causing macular pucker developed after surgical removal in seven eyes and were subsequently removed. A specimen was available for electron microscopic study from four of the seven primary operations and all seven of the repeat operations. The diagnostic associations for the primary cases included retinal holes or tears (four eyes), trauma, inflammation (one eye each). In one eye the membrane was idiopathic. The primary and recurrent ERM specimens contained similar cell types and structural characteristics but were not identical. No one cell type predominated in either primary or recurrent ERM. Compared with studies of idiopathic ERMs, myofibroblasts were present with increased frequency in recurrent membranes. Fibrocytes, fibrous astrocytes, and retinal pigment epithelial cells were also present in most specimens. Other features of both the primary and recurrent ERM specimens included the presence of cells with myoblastic differentiation, fragments of internal limiting membrane, new collagen, and nerve fiber elements.

Diagnosing and treating Phthirus pubis palpebrarum

Phthiriasis palpebrarum is an uncommon cause of blepharitis and conjunctivitis and may easily be overlooked. A high index of suspicion and careful examination of the patients lid margins and eyelashes will lead to the proper diagnosis. Treatment is best accomplished by careful removal of the lice and nits (louse eggs) from the patients lashes. Local application of a pediculocide such as yellow mercuric oxide N.F. 1% ophthalmic ointment applied twice daily for one week or 0.25% physostigmine (Eserine) ointment applied twice daily for a minimum of ten days, to the lid margins should be considered when the total removal of Phthirus pubis and nits is not possible mechanically. Body hair should be examined for infestation with lice and treated with gamma benzene hexachloride shampoo. This medication should be used with caution in infants, children and pregnant women. Family members, sexual contacts, and close companions should be examined and treated appropriately; clothing, linen and personal items should be disinfected with heat of 50 degrees C for 30 minutes.