Pars plana vitrectomy and subretinal surgery for ocular toxocariasis

The clinical course of ocular toxocariasis and the chronological development of peripheral retinal and macular granulomas are reported. Removing the epiretinal as well as subretinal component of the granuloma via pars plana vitrectomy and retinotomy techniques yielded an excellent clinical result. Clinicopathologic correlation of the specimen confirmed the diagnosis with histological evidence of degenerated larval structures in granulomatous inflammation.

Cytotoxic T lymphocytes to endogenous mouse retroviruses and mechanisms of retroviral escape

Mouse retrovirus-induced lymphoma/leukemia and immunodeficiency are useful models for analogous human diseases. Both ecotropic (mouse tropic) and recombinant retroviruses, including the polytropic mink cytopathic focus-inducing type, have been studied for disease pathogenesis and as targets for humoral and cellular immunity, particularly cytotoxic T-lymphocyte (CTL) responses. For AKR/Gross murine leukemia viruses (MuLV) we have defined an immunodominant CTL epitope in the p 15E transmembrane anchor envelope protein and three minor/subdominant epitopes. Evidence is presented for retroviral escape from CTL by selection following genetic recombination and point mutation both within and outside CTL epitope sequences, and via endogenous retrovirus-infected cell downregulation of the generation of anti-AKR/Gross MuLV CTL. As demonstrated in vivo in naturally occurring non-responder strains by adoptive transfer, and in vitro by cell-mixing experiments, a central non-responsiveness mechanism appears to be peripheral inhibition mediated by infected cells expressing MHC-presented viral peptides. Such inhibition requires Fas expression by antiviral T cells; occurs upon TCR-mediated recognition of virus-infected, Fas ligand-expressing "veto" cells; and apparently leads to an antigen-specific form of activation-induced cell death of T cells. In the LP-BM5 MuLV isolate that causes murine AIDS (MAIDS) retroviral variation also leads to CTL escape--the BM5-helper virus has altered forms of the immunodominant and two minor/subdominant epitopes. In contrast, a novel immunodominant CTL epitope is recognized by MAIDS resistant, but not MAIDS-susceptible, strains. This epitope is uniquely encoded in an alternative translational reading frame of the viral gag gene. It also appears that the LP-BM5 MuLV have co-opted the cells of the immune system for retroviral pathogenesis--CD40/CD40L (CD154) interactions are required both for the initiation and progression of MAIDS.

Histopathological features of vitreous removed at macular hole surgery

OBJECTIVE

To describe the histopathological features of the vitreous removed at surgery for macular holes in 200 consecutive cases.

METHODS

The complete vitrectomy specimen in each case was concentrated by means of cellulose membrane filters and stained for light microscopy. The cases were organized into 5 categories: (1) all cases (N = 200), (2) eyes without previous vitrectomy (n = 174), (3) eyes with previous vitrectomy (n = 26), (4) idiopathic cases (n = 143), and (5) traumatic (accidental or surgical) cases (n = 31). The type and frequency of tissue fragments present in the vitreous were determined for each case.

RESULTS

Fibrocellular and cellular membrane fragments were found in a minority of cases in all categories. Retinal fragments were a rare finding, present in only 4 cases. Inflammation was present in 57 (28.5%) of all cases.

CONCLUSIONS

The absence of fibrocellular and cellular membrane fragments in the majority of cases suggests that mechanisms other than cellular proliferation are important in the pathogenesis of macular holes. These fragments are, however, the likely histopathological correlate of the opercula that are often observed clinically in patients with macular hole. Opercula rarely if ever contain retinal fragments, and thus are better termed pseudo-opercula, as has been previously suggested. The cellular proliferation and inflammation that are observed in some of the cases are likely a secondary or reactive process.

Analysis of sex-mismatched human corneal transplants by fluorescence in situ hybridization of the sex-chromosomes

The fate of the cells of corneal transplants has been controversial from the early days of keratoplasty. Various methods such as histological evaluation, radiolabeling of donor cells or Barr-body analysis have been applied to clarify the issue. However, the question whether the transplanted cells are replaced or survive, remains unsolved. In this study, we applied fluorescence in situ hybridization (FISH) of the X- and Y-chromosomes in paraffin sections of explanted sex-mismatched corneal transplants to distinguish between host and donor cells. Fourteen sex-mismatched cases with various reasons for explantation and different postoperative time intervals ranging from 11 months to 30 years were analysed. We found that all cell types, including epithelium, keratocytes and endothelial donor cells were replaced in most cases as early as 1 year after transplantation. In three cases, however, up to 26% of donor keratocytes were still detected up to 4.5 years after transplantation, demonstrating a certain individual variability in the process of replacement. Further studies must show if the extent and timing of donor cell replacement in clinically successful, totally clear transplants is different. Our results are in keeping with the phenomenon of recurrences of corneal dystrophies in the graft, the significant postoperative decline of the endothelial cell density, the fact that typical graft rejections usually take place within 1-2 years postoperatively and that relatively late rejections can occur in rare cases probably due to some surviving stromal keratocytes. Donor cell replacement is a special feature of corneal transplants when compared with other kinds of organ transplants and might be due to the presence of the same tissue type in the immediate neighbourhood of the graft.

Photocoagulation of well-defined choroidal neovascularization in age-related macular degeneration: clinicopathologic correlation

PURPOSE

To present the clinicopathologic features of the eyes of a patient with age-related macular degeneration (ARMD): the right eye was treated for well-defined extrafoveal choroidal neovascularization (CNV), and the left eye had an untreated disciform scar.

METHODS

The patient was studied ophthalmoscopically and by fluorescein angiography at the time of presentation and on follow-up examinations up to 54 days after laser treatment, when he died. The posterior portions of both eyes (obtained postmortem), including the macula and optic nerve head, were sectioned serially for light microscopy. Tissue sections from both eyes were removed from glass slides and studied by transmission electron microscopy.

RESULTS

Histopathologic study of the right eye disclosed a thin layer of basal laminar deposit throughout the posterior pole. Two defects in Bruch's membrane without CNV were present within the area of laser photocoagulation located superior to the fovea. No CNV was present in the scar. Eleven areas of early CNV were present in the posterior pole. Histopathologic study of the left eye showed a prominent basal laminar deposit throughout the posterior pole. A 2.6 x 2.7 mm disciform scar was present that was located mostly in the subretinal space. Four sources of CNV were present.

CONCLUSIONS

The clinicopathologic features of a treated eye with well-defined extrafoveal CNV, and the fellow eye with a disciform scar, both associated with ARMD, are presented. Although laser treatment obliterated a choroidal neovascular membrane, 11 additional areas of early, subclinical CNV were present.

Histopathologic and ultrastructural findings of surgically excised choroidal neovascularization. Submacular Surgery Trials Research Group

OBJECTIVE

To study the histologic and ultrastructural features of surgically excised choroidal neovascularization (CNV) from patients who had undergone submacular surgery.

MATERIALS AND METHODS

Voluntarily submitted surgically excised CNV specimens from a subset of specimens obtained by the Submacular Surgery Trials Research Group between January 1, 1994, and December 31, 1996, were available for this study. The specimens were routinely processed for transmission electron microscopic examination. The largest horizontal and vertical dimensions, cellular and extracellular constituents, and relationship of the CNV to the neurosensory retina and retinal pigment epithelium (RPE) were recorded.

RESULTS

Seventy-eight surgical specimens were obtained from 160 patients treated surgically in Submacular Surgery Trials centers. Sixty-one (78%) were from patients with age-related macular degeneration (ARMD) and 17 (22%) were from patients with ocular histoplasmosis syndrome or idiopathic causes (hereafter referred to as the non-ARMD group). The histologic diagnosis was fibrovascular tissue, fibrocellular tissue, or hemorrhage in all cases. Vascular endothelium and RPE were the most common constituents of the CNV. Basal laminar deposit was only present in CNV from patients with ARMD. Age-related macular degeneration specimens were larger (mean +/- SD, 2042 [+/- 1175] x 320 [+/- 185] microm vs 1498 [+/- 792] x 227 [+/- 166] microm) and were more likely to have a sub-RPE (beneath the RPE) component than non-ARMD specimens.

CONCLUSIONS

All evaluated surgically excised CNV specimens in this study from patients enrolled in the Submacular Surgery Trials consisted of fibrovascular tissue, fibrocellular tissue, or hemorrhage. Surgically excised CNV associated with ARMD in this series was larger and often was located beneath the RPE compared with non-ARMD CNV, although fewer than half of all the specimens could be oriented by topographic relationship to the RPE.

HIV-1-associated Kaposi's sarcoma in a predominantly black population at an inner city hospital

BACKGROUND

Kaposi's sarcoma (KS) associated with human immunodeficiency virus type 1 (HIV-1) is the most common malignancy in patients with AIDS. It has been most commonly reported in white homosexual men, though a few cases have been reported in blacks.

METHODS

We conducted a retrospective analysis of all HIV-1 seropositive patients with biopsy-proven KS seen at Howard University Hospital between February 1985 and June 1995.

RESULTS

Of the 73 patients identified, 66 (90%), 4 were white, 2 were Hispanic, and 1 was of unidentified race. The median age was 32 years. Forty-eight (66%) were homosexual or bisexual men, and 10 (14%) were homosexual or bisexual with a history of intravenous drug use (IDU). A history of IDU or blood transfusion was the only risk factor in 7 (9%) and 2 (3%), respectively. The other 6 (8)% were heterosexual. The median survival was 2.2 years. A CD4 count <200 and the presence of an opportunistic infection were associated with shortened survival.

CONCLUSIONS

The predominant risk factor for HIV-1-associated KS was homosexual or bisexual activity. Only a few women with KS were identified, and they also reported sexual transmission from male bisexuals and/or drug users. Poor survival was associated with CD4 <200, stage III and IV KS at presentation, and opportunistic infections.

CHARGE association: histopathological report of two cases and a review

BACKGROUND

The CHARGE association (C = coloboma, H = heart disease, A = atresia or stenosis of the choanae, R = retarded growth and development or CNS anomalies, G = genital hypoplasia, and E = ear anomalies or deafness) is a rare, recently well-recognized clinical study. The ophthalmic abnormalities have been described in numerous reports, but the ocular histopathologic findings have not been presented in detail.

METHODS

We conducted gross and microscopic studies of eyes of two patients with the CHARGE association obtained postmortem.

RESULTS

The eyes in one case had a small, symmetrical, inferior nasal coloboma of the choroid. In the other case, extensive inferior nasal colobomas of the iris, ciliary body, and choroid with retinal dysplasia, ectopic retinal/glial tissue in the sclera and hypoplasia of the optic nerve head were present.

CONCLUSION

We document the histopathological features of eyes of two subjects with the CHARGE association. The abnormalities of these eyes were typical ocular colobomas presumably resulting from the failure of complete closure of the optic fissure.

Evidence for a continued requirement for CD40/CD40 ligand (CD154) interactions in the progression of LP-BM5 retrovirus-induced murine AIDS

In genetically susceptible C57BL/6 mice the LP-BM5 isolate of murine retroviruses causes profound splenomegaly, lymphadenopathy, hypergammaglobulinemia, and an immunodeficiency syndrome bearing many similarities to the pathologies seen in AIDS. Because of these similarities, which also include terminal B cell lymphoma formation, this syndrome has been called murine AIDS or MAIDS. Prompted by previous reports showing that the onset of MAIDS is dependent on the presence of both CD4+ T and B cells, we have previously shown that anti-gp39/CD40 ligand mAb (anti-CD40L mAb) treatment of LP-BM5-infected mice is effective in inhibiting the induction of MAIDS when a short course of anti-CD40L mAb treatment was started on the same day as LP-BM5 administration. The success of anti-CD40L mAb therapy, as indicated by a much reduced degree of splenomegaly, hypergammaglobulinemia, and mitogen and allogeneic CTL unresponsiveness, demonstrated that CD40L/CD40 interactions were critical to the establishment of MAIDS. Here we extend these findings through the use of delayed anti-CD40L mAb treatment of mice, beginning 3-4 weeks after LP-BM5 infection, by showing that interruption of CD40L/CD40 interactions also interferes with the progression of MAIDS. About 60% of LP-BM5-preinfected mice were affected by delayed anti-CD40L mAb treatment, with substantially reduced spleen weights and serum hypergammaglobulinemia and normal or greatly restored proliferative responses to Con A stimulation and CTL responses to allogeneic stimulation. The other LP-BM5-infected mice that did not respond to anti-CD40L therapy were found to have made antibodies to the anti-CD40L mAb. Thus, in a majority of mice anti-CD40L mAb therapy was very effective in interfering with MAIDS pathogenesis well after the establishment of the virus infection and MAIDS symptomatology, indicating that CD40L/CD40 interactions are crucial to the maintenance and progression of the disease, as well as its initiation.

Tick infestation of the eyelid

PURPOSE

To report the rare occurrence of tick infestation of the eyelid margin.

METHODS

A 58-year-old woman was initially examined with a small yellow lesion of the left upper eyelid margin that appeared after she felt a sting near her eye. Close examination disclosed an insect body attached to the eyelid margin. En bloc excision of the insect with part of the eyelid was performed.

RESULT

Gross examination of the specimen identified the organism as the nymph stage of a bloated tick of the genus Hyalomma but of an uncertain species.

CONCLUSION

Ticks (Hyalomma) can become embedded in the meibomian gland orifice and manifest as a mass at the eyelid margin.

Clinicopathologic correlation of chorioretinitis sclopetaria

PURPOSE

To report the clinicopathologic features in the eye of a patient who sustained a traumatic chorioretinal rupture from a gunshot wound to the orbit, chorioretinitis sclopetaria, with clinical follow up of more than 20 years.

METHODS

The patient was studied ophthalmoscopically and by fluorescein angiography after the trauma and was seen intermittently thereafter. The eyes were obtained postmortem; sections of the central portion of the right eye, including the macula and optic nerve head, and the inferior cap were examined by light microscopy.

RESULTS

Histopathologic study of the right eye showed partial loss of the nerve fiber and ganglion cell layers in the macular area, temporal peripapillary and macular loss of the photoreceptors with hypertrophy and hyperplasia of the retinal pigment epithelium, an epiretinal membrane, and three defects in Bruch's membrane. Inferiorly, there was a 5-mm defect in choroid, Bruch's membrane, and retina. These structures were replaced by a loose and dense fibrous connective tissue. The sclera and a long posterior ciliary nerve remained intact. A thin fibrovascular tissue from the choroid extended into the subretinal space where it was covered by retinal pigment epithelium and thickened basement membrane in the posterior aspect of the inferior lesion. Marked hemiatrophy of the optic nerve was present.

CONCLUSIONS

The clinicopathologic features of chorioretinitis sclopetaria include direct traumatic chorioretinal rupture followed by marked fibrovascular proliferation with variable replacement of choroid and retina with no retinal detachment. Posteriorly, indirect macular choroidal ruptures with hyperplasia and migration of the retinal pigment epithelium into the retina and choroid, epiretinal membrane formation, loss of photoreceptors, and marked hemiatrophy of the optic nerve were present.

An alternative translational reading frame encodes an immunodominant retroviral CTL determinant expressed by an immunodeficiency-causing retrovirus

Recognition of virus-infected or transformed cells by CD8+ CTL requires a trimolecular complex composed of MHC class I, beta2-microglobulin, and a specific foreign peptide composed of 8 to 10 linear amino acids. The generation of such CTL epitopes has traditionally been thought to be from the primary open reading frame encoding the viral or tumor-associated proteins. In this report it is demonstrated that a viral CTL epitope can also be generated from an alternative reading frame. Using a combination of synthetic peptides and Sindbis or vaccinia expression systems, MHC class I Kd-restricted BALB/cByJ CTL directed against defective gag gene constructs of the LP-BM5 virus complex that causes murine AIDS were shown to have specificity for the antigenic peptide SYNTGRFPPL. This epitope is generated in a novel fashion from the second open reading frame (ORF2) of both the defective and ecotropic helper virus components of LP-BM5. Importantly, lysis of target cells expressing BM5 ecotropic helper, and/or defective viral gag, demonstrated that the SYNTGRFPPL epitope is generated during the course of a normal retroviral infection. Furthermore, MAIDS-resistant BALB/cByJ mice also generated secondary restimulated CTL specific for SYNTGRFPPL following in vivo priming with the LP-BM5 retroviral complex. These data suggest that retroviruses, and potentially other viruses and foreign genes, are capable of expressing T cell epitopes from alternative open reading frames. If one considers the influence of self peptides on T cell development, these "alternative reading frame-derived" peptides could provide an important additional influence on the functional T cell repertoire.

Ocular explosion during cataract surgery: a clinical, histopathological, experimental, and biophysical study

INTRODUCTION

An increasing number of cases are being recognized in which a peribulbar anesthetic for cataract surgery has been inadvertently injected directly into the globe under high pressure until the globe ruptures or explodes. We reviewed the records of 6 such cases (one of which was reported previously by us), and one additional case has been reported in the literature. Surprisingly, 2 of these 7 cases went unrecognized at the time, and the surgeons proceeded with the cataract operation; all of the patients ultimately developed severe visual loss and/or loss of the eye.

OBJECTIVES

To reproduce this eye explosion in a live anesthetized rabbit model and to perform a clinical, histopathological, experimental, biophysical, and mathematical analysis of this injury.

METHODS

Eyes of live anesthetized rabbits were ruptured by means of the injection of saline directly into the globe under high pressure. The clinical and pathological findings of the ruptured human and animal eyes were documented photographically and/or histopathologically. An experimental, biophysical, and mathematical analysis of the pressures and forces required to rupture the globe via direct injection using human cadavers, human eye-bank eyes, and classic physics and ophthalmic formulas was performed. The laws of Bernoulli, LaPlace, Friedenwald, and Pascal were applied to the theoretical and experimental models of this phenomenon.

RESULTS

The clinical and pathological findings of scleral rupture, retinal detachment, vitreous hemorrhage, and lens extrusion were observed. In the exploded human and rabbit eyes, the scleral ruptures appeared at the equator, the limbal area, or the posterior pole. In 2 of the 7 human eyes, the anterior segments appeared entirely normal despite the rupture, and cataract surgery was completed; surgery was canceled in the other 4 cases. In 4 of the 5 injected and ruptured rabbit eyes, the anterior segments appeared essentially normal. The experiments with human eye-bank eyes and the theoretical analyses of this entity show that the pressure required to produce such an injury is much more easily obtained with a 3- or 5-mL syringe than with a syringe 10 mL or larger.

CONCLUSIONS

Explosion of an eyeball during the injection of anesthesia for ocular surgery is a devastating injury that may go unrecognized. The probability of an ocular explosion can be minimized by careful use of a syringe 10 mL or larger with a blunt needle, by discontinuing the injection if resistance is met, and by inspecting the globe prior to ocular massage or placement of a Honan balloon. When ocular explosion occurs, immediate referral to and intervention by a vitreoretinal surgeon is optimal. Practicing ophthalmologists should be aware of this blinding but preventable complication of ocular surgery.

Familial Axenfeld-Rieger anomaly, atrial septal defect, and sensorineural hearing loss: a possible new genetic syndrome

OBJECTIVE

To describe the clinical and ocular histopathological findings in multiple members of a family with congenital Axenfeld-Rieger anomaly, atrial septal defect, and sensorineural hearing loss.

METHODS

We performed a retrospective review of the medical charts and the ocular histopathological material of multiple members of a family.

RESULTS

Congenital Axenfeld-Rieger anomaly and glaucoma were inherited by both the proband and her male half-sibling from a phenotypically positive father and 2 different phenotypically negative mothers, suggesting an autosomal dominant inheritance. The proband's male half-sibling and her father also had atrial septal defects and sensorineural hearing loss. The proband's paternal grandmother had severe glaucoma. Histopathological analysis of blind, painful eyes removed from the proband's father and paternal grandmother showed incomplete development of the anterior chamber angle with iris stromal hypoplasia, prominent posterior embryotoxon with iris adhesions, and abnormal position and insertion of the ciliary muscles.

CONCLUSIONS

This is the first description of coexisting Axenfeld-Rieger anomaly, atrial septal defect, and sensorineural hearing loss in multiple members of a single family. The iris, trabecular meshwork, and large portions of the cardiac intraventricular septum all arise from neural crest anlagen, thus supporting the notion that anterior segment dysgenesis represents a developmental disorder of the neural crest.

Ocular involvement in familial erythrophagocytic lymphohistiocytosis

BACKGROUND

Familial erythrophagocytic lymphohistiocytosis (FEL), a rare, rapidly fatal childhood disorder, is characterized by intermittent fevers, hepatosplenomegaly, cytopenia, hypercytokinemia and lymphohistiocytic infiltration with erythrophagocytosis involving multiple organs. We report the clinical and histological features of two infants with FEL and emphasize the ocular findings.

METHODS

Microscopic examination of formalin-fixed, paraffin-embedded autopsy material was performed. Immunohistochemical studies were performed in case 1.

RESULTS

The first patient presented with clinical and laboratory features and a family history consistent with FEL, and a liver biopsy revealed a lymphohistiocytic infiltrate with erythrophagocytosis consistent with FEL. A deceased brother had been diagnosed with FEL. Autopsy showed widely disseminated lymphohistiocytic infiltrates affecting the liver, spleen, bone marrow, lungs, kidneys and brain. Histologic examination of both eyes disclosed a prominent lymphohistiocytic infiltrate of the optic nerve with destruction of nerve fiber bundles as well as milder infiltrates in the choroid, scleral canals, perineural areas in the orbit and the optic nerve head perivascularly. The second patient also had the typical clinical, laboratory and autopsy findings with similar involvement of most organs, including extensive infiltration of the spleen and bone marrow. Histologic examination of one eye revealed marked lymphohistiocytic infiltration of the entire choroid as well as milder infiltration in the trabecular meshwork, iris, ciliary body, optic nerve, meninges and around the central retinal vein in the optic nerve.

CONCLUSION

The findings of this study further define the ocular pathologic features of FEL, which are a part of a generalized, multiorgan disseminated disease.

The role of proximal and distal sequence variations in the presentation of an immunodominant CTL epitope encoded by the ecotropic AK7 MuLV

An emv-14-derived, replication-competent ecotropic murine leukemia virus [MuLV], designated AK7, was previously cloned from the AKXL-5 recombinant inbred mouse strain and partially characterized. While genetically encoding for an envelope-derived immunodominant CTL epitope [KSPWFTTL] located in the transmembrane region of p15TM, this virus, unlike the emv-11-derived virus AKR623, fails to be efficiently recognized by AKR/Gross MuLV-specific cytotoxic T lymphocytes [CTL]. AK7 thus provides the opportunity to study the role of retroviral sequence variations that are located outside of the immunodominant epitope as a mechanism of escape from CTL-mediated immune surveillance. In an attempt to identify which region[s] of the AK7 genome could account for its ability to evade efficient recognition by AKR/Gross MuLV-specific CTL, we have constructed recombinant murine retroviruses. The direct influence of a sequence variation twelve amino acids N-terminal to KSPWFTTL was explored with the use of chimeric viruses and determined not to significantly impair the presentation of KSPWFTTL to AKR/Gross MuLV-specific CTL. The long terminal repeat [LTR] derived from the AK7 virus, which possesses only one copy of the 99-base pair transcriptional enhancer in the U3 region, in contrast to AKR623 that possesses two copies of the tandem direct repeat enhancers, was also analyzed for its influence on the presentation of KSPWFTTL. Interestingly, our data indicate that the enhancer region derived from AK7 negatively influences the presentation of KSPWFTTL in the context of a recombinant AKR623 virus.

Clinicopathological correlation of technetium bone scan in vascularization of hydroxyapatite implants. A primate model

OBJECTIVES

To report the histopathological and bone scan characteristics of the stages of hydroxyapatite fibrovascular integration and to consider the implications for the timing of peg drilling in a primate model.

DESIGN

Three monkeys received hydroxyapatite implants covered only anteriorly with a fascia lata button to which the rectus muscles were sutured. Weekly bone scans were evaluated quantitatively and qualitatively. The orbits were harvested at 2, 4, and 8 weeks and examined histopathologically.

RESULTS

Quantitatively, the implant's technetium uptake increased, then reached a plateau by 4 weeks. Peripheral uptake was present on the images and histologically at 2 weeks. When bone scan images suggested complete vascularization by the fourth week, the implant was 99% vascularized histologically. Completion of vascularization was ascertained at 8 weeks, without further discernible changes in the bone scans.

CONCLUSIONS

The technetium bone scan is sensitive to the vascularization of the hydroxyapatite implant and discerns when complete vascularization is approached. This primate study models closely the clinical findings we have recently reported. We advocate at least a 4-week interval between the time the bone scan suggests full vascularization and peg drilling.

Endothelial metaplasia in the iridocorneal endothelial syndrome

PURPOSE

To test the hypothesis that the aberrant, cytokeratin-expressing cells that replace endothelium in the iridocorneal endothelial (ICE) syndrome are of endothelial origin.

METHODS

Corneas from four patients with Chandler's syndrome and three with essential iris atrophy were examined by two-color immunofluorescence for simultaneous expression of cytokeratins and two markers of endothelial lineage: vimentin and the antigen recognized by the antiendothelial monoclonal antibody 2B4.14.1.

RESULTS

In six corneas, unequivocal endothelial staining for cytokeratins was present; in each of these, cells coexpressing cytokeratins and the two endothelial markers were clearly identifiable. In the remaining cornea, weak cytokeratin staining that colocalized with vimentin was present.

CONCLUSIONS

These results lend strong support to the hypothesis that the "epithelial-like" endothelial cells in ICE syndrome are cells of endothelial lineage rather than heterotopia of epithelial cells; these cells probably arise via a metaplastic transformation of preexisting endothelium.

Central cloudy corneal dystrophy of Francois. A clinicopathologic study

Central cloudy corneal dystrophy of Francois was first described in 1955 by J. Francois; its pathophysiology remains unknown. An 80-year-old woman with bilateral central cloudy corneal dystrophy of Francois was examined after having undergone a combined penetrating keratoplasty and cataract extraction. The corneal button was obtained. Light microscopy revealed stromal staining for acid mucopolysaccharide. Transmission electron microscopy revealed extracellular vacuoles, some of which had fibrillogranular material and electron-dense deposits. Fibrillogranular material was present in and around some keratocytes. Numerous endothelial vacuoles contained light-staining fibrillogranular material and round electron-dense granules. Our findings suggest that the opacities in patients with central cloudy corneal dystrophy of Francois are due to the extracellular accumulation of mucopolysaccharide and lipidlike material. Further studies are needed to elucidate the nature of these deposits.

Extrusion of abnormal endothelium into the posterior corneal stroma in a patient with posterior polymorphous dystrophy

PURPOSE

To report the presence of abnormal endothelium that extruded into the posterior corneal stroma in a patient with posterior polymorphous dystrophy.

METHODS

The corneal button of a man who underwent penetrating keratoplasty for posterior polymorphous dystrophy was examined by light and electron microscopy. Immunoperoxidase staining for cytokeratins, vimentin, and the endothelial antigen recognized by monoclonal antibody 2B4.14.1 antigen was performed. Two-color immunofluorescence staining for simultaneous detection of cytokeratins and 2B4.14.1 antigen was also done.

RESULTS

Much of the endothelium had characteristic features of epithelium-like cells, and abnormalities in Descemet's membrane were present. Curious oval and slit-like spaces in the posterior stroma were lined by epithelium-like endothelial cells and were continuous with the anterior chamber through defects in Descemet's membrane.

CONCLUSION

These abnormalities in the posterior stroma have not previously been described in histopathologic reports of posterior polymorphous corneal dystrophy and are likely an unusual variation in the spectrum of this hereditary disorder.

Clear cell differentiation in choroidal melanoma. COMS report no. 8. Collaborative Ocular Melanoma Study Group

OBJECTIVE

To describe 2 enucleated eyes of patients enrolled in the Collaborative Ocular Melanoma Study that contained primary choroidal melanoma with clear cell features.

METHODS

During a 9-year period, 1493 eyes enucleated as part of the Collaborative Ocular Melanoma Study routinely processed for histologic examination were evaluated by the pathology review committee (H.E.G, D.M.A, and W.R.G). Two eyes with unusual variants of choroidal melanoma were identified and immunostained for S100 protein and HMB 45. Portions of the tumors were processed for electron microscopic examination.

RESULTS

Results of electron microscopic examination of both tumors displayed malignant melanoma (mixed cell type with many malignant cells with clear cytoplasm). The cytoplasm of the clear cells stained with periodic acid-Schiff and failed to stain when pretreated with diastase. Results of immunohistochemical stains in both tumors were positive for S100 protein and HMB 45 in the tumor cells. Results of electron microscopic examination showed that the cytoplasm of the clear cells contained scattered glycogen granules, premelanosomes, and melanosomes.

CONCLUSION

These cases represent a clear cell variant of malignant melanoma of the choroid. This tumor should not be confused with metastatic clear cell carcinoma to the choroid.

Familial internal limiting membrane dystrophy. A new sheen retinal dystrophy

OBJECTIVE

To describe the clinicopathologic features of a previously unreported retinal dystrophy.

METHODS

Fourteen members of a single family were examined. The medical records of 2 additional family members were reviewed. Pathologic examination was performed on 2 eyes of 1 affected patient.

RESULTS

Five individuals were identified with a retinal dystrophy characterized by a glistening inner retinal surface throughout the posterior pole. Visual loss occurred in 3 affected patients in later life owing to superficial polycystic retinal edema and retinal folds. Electroretinographic testing revealed a selective diminution of the b wave. Pathologic examination revealed an abnormal internal limiting membrane with schisis cavities in the inner retina. Endothelial cell swelling, pericyte degeneration, and basement membrane thickening were present in retinal capillaries.

CONCLUSIONS

A previously unreported sheen retinal dystrophy is described. Pedigree analysis suggests an autosomal dominant mode of inheritance. A primary defect in Müller cells is the suspected, but unproved, cause. No effective treatment for the associated visual loss is known. The term familial internal limiting membrane dystrophy is proposed to describe this condition.

Histopathologic and electron-microscopic features of corneal and scleral collagen fibers in osteogenesis imperfecta type III

BACKGROUND

This report describes the histopathologic and electron-microscopic features of an eye from a patient with osteogenesis imperfecta type III. In particular, the diameters of corneal stromal and scleral collagen fibers were determined.

METHODS

The eyes of an 18-year-old white male with osteogenesis imperfecta type III were examined by light and electron microscopy and the pathological features were compared with an age-matched control eye.

RESULTS

The cornea was clear. The sclera had a blue color and was moderately thinned, especially at the equator. Light microscopy revealed absence of Bowman's layer. Transmission electron microscopy confirmed complete absence of Bowman's layer without evidence of scarring or inflammation. The collagen fibers of the corneal stromal lamellae were about 25% narrower than in the control, but the cornea was otherwise unremarkable ultrastructurally. The collagen fibers of the sclera were approximately 50% narrower than in the control and were much more uniform in size. Prominent portions of elastic fibers, which are usually only present in a small number in the inner portion of the sclera, were present throughout the sclera.

CONCLUSION

We propose that it is the uniformity of the scleral collagen fibers which gives the sclera translucence, producing the blue color often observed clinically in osteogenesis imperfecta. Absence of Bowman's layer of the cornea did not interfere with the stability of the cornea in this case. This appears to be the first published pathological examination of the eye in osteogenesis imperfecta type III.