Long-term ultrastructural changes in human corneas after tattooing with non-metallic substances

AIM

To investigate the ultrastructural appearance and the deposition pattern of dye particles in long term non-metallic corneal tattooing.

METHODS

Two tattooed human corneas were obtained by keratoplasty. One corneal button was fixed in Karnovsky's solution and the other in Trumps' solution. Both corneas were divided and processed for conventional light (LM) and transmission electron microscopy (TEM). Five additional formalin fixed corneas with tattoos were retrieved from paraffin for TEM. The time between tattoo and removal of the corneal button/enucleation ranged from 7 to 61 years. All seven corneas were examined using a Jeol JCXA733 microprobe for wave length dispersive analysis in order to exclude any presence of metallic salts in the tattooed area.

RESULTS

Histologically, clumps of brown-blackish granules were present mainly in the mid stroma, but also in anterior and partially in the posterior half of the stroma. On TEM, numerous round and oval electron dense particles were seen in the cytoplasm of keratocytes arranged as clusters or large islands. The larger particles appeared black, while the smaller particles were grey. In well fixed tissue a unit membrane was observed around these clusters. No granules were detected in the extracellular matrix.

CONCLUSIONS

Keratocytes can actively ingest and retain tattooing particles of non-metallic dyes within their cell membrane for very long periods of time.

Primary conjunctival rhabdomyosarcoma: 2.5 years' follow-up after combined chemotherapy and brachytherapy

BACKGROUND

The 2.5-year outcome of a 3-year-old girl with a primary intraconjunctival rhabdomyosarcoma treated by biopsy-controlled combined chemo- and brachytherapy is reported.

METHODS

The patient presented with a conjunctival dermoid-like lesion which showed modest growth on 1-month follow-up. The first biopsy appointment was missed because of a viral illness. When she showed up 3 months later a further increase in size was obvious and several incisional biopsies were taken immediately.

RESULTS

Light microscopy revealed an undifferentiated subepithelial small cell tumour. On immunohistochemistry the tumour reacted with vimentin and desmin antibodies. Thus, the diagnosis of an embryonal rhabdomyosarcoma was made. The patient underwent 9 cycles of polychemotherapy and the tumour mass disappeared macroscopically. However, immunohistochemistry of incisional biopsies showed residual tumour cells. The latter were eradicated by an individually shaped strontium-90 applicator.

CONCLUSION

At 2.5 years after biopsy-controlled combined chemotherapy and brachytherapy the patient is free of tumour at a manageable level of complications. This new approach appears to be a good alternative in the treatment of primary conjunctival rhabdomyosarcomas since it takes advantage of the unique location of this rare tumour and avoids hemifacial retardation, known to be induced by external beam radiation.

Hydroxyapatite orbital implant. A light- and electron-microscopic and immunohistochemical study

OBJECTIVE

This study aimed to characterize the constituents of the ingrown host tissue in explanted orbital coral spheres by means of light electron microscopy and immunohistochemistry and to compare findings at different intervals after implantation.

DESIGN AND METHODS

A microscopic retrospective laboratory study of three explanted coral spheres from three different patients was undertaken. The first specimen was an infected hydroxyapatite orbital implant, which was removed after 18.5 months and processed for standard light microscopy and transmission electron microscopy. Immunohistochemistry was performed using vimentin, actin, CD-68, and CD-34 marker. Two other explanted spheres (after 3 weeks and 2.5 months) were examined by light microscopy only, because no fibrovascular ingrowth could be detected.

RESULTS

On light microscopy, the pores of the first coral were filled entirely with the fibrovascular tissue. A basophilic line reminiscent of calcium deposition was seen along hydroxyapatite spicules, where it often was associated with newly formed bony lamellae. Similar lines were seen partially in the 2.5-month specimen but not in the 3-week specimen. Immunohistochemistry of the first specimen enhanced visualization of the capillary network when the CD-34 marker was used. The fibrovascular tissue was uniformly vimentin-positive and partially actin-positive. On transmission electron microscopy, typical fibroblasts and myofibroblasts were observed. The latter were separated by thin sheets of banded collagen and formed pseudoepithelial structures. Proliferating vessels often showed high endothelial cells.

CONCLUSIONS

The fibrovascular ingrowth contains not only vimentin-positive regular fibroblasts but also actin-positive myofibroblasts. Interaction between the invading tissue and hydroxyapatite structures leads to long-term ossification.

Orbital tumour as a presenting symptom of breast carcinoma: value of detecting hormone receptors

A 54-year-old woman was referred for evaluation of an orbital tumour after 5 months of non-specific ophthalmic symptoms. Tissue obtained by an open orbital biopsy was highly suspicious for asymptomatic metastatic breast carcinoma, which was discovered a few weeks later. Unlike the primary tumour, which was an invasive lobular breast carcinoma, the metastatic tissue was repeatedly negative for oestrogen and progesterone receptor markers. A possible reason is a change in cellular cytoplasmic and nuclear protein composition during the metastatic process. Since the primary tumour was positive for the hormone receptors, the patient was treated by chemotherapy and tamoxifen. The follow-up supports a favourable effect of adjuvant endocrinological therapy even in cases with receptor-negative metastatic tissue. This report is in partial contradiction to some previously published cases and emphasises the role of receptor status in the primary tumour.

Capillaries in the epithelium of pterygium

AIM

To present new morphological observations of intraepithelial capillaries in pterygium and to provide some explanations for this phenomenon.

METHODS

The ultrastructural features of pterygia from 26 patients were examined. Surgically excised tissue was processed for conventional light and transmission electron microscopy.

RESULTS

Individual capillaries within the epithelium of the anterior half towards the head of pterygia were identified in 11 specimens out of 26 pterygia examined (42.3%). The perivascular connective tissue of the intraepithelial capillaries contained fibroblasts, collagen fibrils, and elastin-like material. Epithelial cells surrounding these capillaries showed defects in the basal lamina in contrast with the continuous basal lamina of the endothelium. In the intercellular space of the epithelium an amorphous substance, occasional fibroblast processes, and collagen fibrils were frequently observed.

CONCLUSION

Capillaries in the epithelium of pterygia are rare, but not exceptional. The ingrowth of these vessels from the stroma into the epithelium can be interpreted as a reaction to hypoxia or deficiency of any other substance transported via the bloodstream. Apparently, the perivascular connective tissue can be used by ingrowing fibroblasts as a migration pathway. The migrating fibroblasts appear to use the defects of the epithelial basal lamina (whether partially or complete) in order to reach the intercellular space. It is possible that collagen fibrils in the epithelial intercellular space have been laid down by fibroblasts which contribute to the pathological dedifferentiation of the conjunctival epithelium.

Immunomodulating activity of allopurinol in experimental lens-induced uveitis

PURPOSE

The aim of this study was to evaluate the immunomodulating activity of allopurinol using a model of lens-induced uveitis (LIU) and to compare these effects to those of steroids.

METHODS

We tested the sera of both LIU and control rats against western blots (WB) of SDS-PAGE separations of protein fractions from normal and LIU rat lenses. These blots were scanned using digital image analysis. A newly developed technique was used to compare the complex autoantibody (AAB) repertoires. Five groups of LIU rats were investigated: no treatment; single doses of methylprednisolone (MPR; 7.5 mg/kg body wt.i.v.); allopurinol (AL; 50 mg/kg body wt. i.v.); a combination of both drugs (AL and MPR); repeated application of AL (ALFR; 50 mg/kg body wt.i.v. every 2 weeks during the immunization period and a daily dose of approx. 25 mg/kg body wt. orally).

RESULTS

Immunization induced complex antibody repertoires against lens proteins. Antibody repertoires of LIU rats were identical, regardless of whether the proteins were obtained from control, uveitis eyes, or corresponding healthy eyes of the same individual. AL showed a dose-dependent immunological effect in LIU treatment. Given as a single dose, AL revealed no significant change in the AAB repertoire; however, ALFR showed very clear modification of the AAB repertoires compared to both controls and rats receiving steroids.

CONCLUSIONS

These results suggest dose-dependent effects of allopurinol in LIU treatment. Repeated application during the immunization period induced a strong immunomodulating effect of AL that was not observed after single doses.

Monoclonal corneal gammopathy: topographic considerations

Desposition of immunoglobulins in the cornea occasionally occurs in benign and malignant lymphoproliferative conditions. A 52-year-old woman with recently discovered monoclonal gammopathy of undetermined significance (MGUS) was referred to our hospital. Slit-lamp and ultrasound biomicroscopy revealed bilateral deposits within all corneal layers. The precipitates were organized in a circle, leaving a perilimbal zone and the axial cornea clear. Light microscopy of a biopsy disclosed confluent subepithelial deposits and defects in Bowman's layer. Immunoperoxidase reaction was positive only for IgG and IgG-kappa. Transmission electron microscopy confirmed the presence of extracellular rectangular and arcuate immunoglobulin crystalloids with a 10-nm periodicity but a non-crystalline defraction pattern. A review of the literature showed that the circumferential pattern of immunoglobulin deposition is associated with short-term visual symptoms and good visual acuity. The present report supports a hypothesis of immunoglobulin deposition via the limbal arcade and contradicts the "tear theory."

Effects of allopurinol and steroids on inflammation and oxidative tissue damage in experimental lens induced uveitis: a biochemical and morphological study

AIMS

To evaluate the effects of allopurinol in lens induced uveitis (LIU) by morphological methods and to compare these effects with those of steroids and a combination of both drugs biochemically and morphologically.

METHODS

Lipid peroxides (LPO) of the retinal tissue were determined by two different methods (thiobarbituric acid assay (TBA) and high performance liquid chromatography expressed as malondialdehyde-like substances). Myeloperoxidase (MPO) activity in the iris/ciliary body complex was analysed spectrophotometrically. Histological changes on three morphological levels of LIU eyes were evaluated.

RESULTS

Both allopurinol and the combination of allopurinol/prednisolone led to a significant reduction in the increaed retinal LPO values. Prednisolone only revealed significant effects on retinal LPO when being measured with the TBA method. MPO activity in iris and ciliary body was significantly reduced in all therapy groups. The morphological evaluation of the sections by two masked investigators revealed a significant reduction (p < 0.05) in the inflammation score in all therapy groups. Morphometric studies using the QUANTIMED system (Leica, Cambridge) showed significantly reduced values (p < 0.05) in the allopurinol group and in the group receiving prednisolone and allopurinol. Prednisolone alone did not lead to a significant reduction in the values.

CONCLUSIONS

The findings show that both allopurinol and steroids exert positive effects on the variables determined in LIU. The effects of steroids are believed to be mostly due to their direct action on inflammatory cells. The recently reported scavenging effects of methylprednisolone should play a minor role in this disease model. Allopurinol and oxypurinol act as direct scavengers of free radicals and hypochlorous acid, which is produced via MPO catalysis, thus leading to a reduction in tissue inflammation and tissue damage.

Hemangiopericytoma of the inner canthus

PURPOSE

A 31-year-old woman with a mass at the left inner canthus was referred to our hospital.

METHODS

Clinical examination failed to establish a diagnosis and the patient underwent an incisional biopsy.

RESULTS

Histopathologic examination disclosed a hemangiopericytoma.

CONCLUSIONS

Because the behavior of a hemangiopericytoma is unpredictable, this tumor should be included when making a differential diagnosis in lesions of the inner canthus.

Misleading aspiration biopsy in combined intraocular pathology

Images

[Traumatic wound dehiscence and corneal rupture 3 1/2 years after radial keratotomy]

BACKGROUND

Severe complications such as a traumatic wound dehiscence have been described very rarely after radial keratotomy. The following case demonstrates for the first time that wound healing is not completed even 31/2 years postoperatively and that therefore an ocular blunt trauma may still cause a dehiscence of the radial incisions.

CASE REPORT

A 22-year-old patient presented in July 1993 to our emergency unit because of a corneal perforation in his right eye after a blunt trauma. His past medical history was significant for radial keratotomy surgery performed in January 1990 to correct a bilateral low-degree myopia (OD = -3.25 D; OS = -3.75 D). At surgery a horizontal rupture running through the entire cornea and including the two radial keratotomies at the 3 and 9 o'clock position was evident. The whole iris and lens were missing. The retina was completely detached. The corneal laceration was sutured. Twelve days later the retina was reattached with an encircling band, vitrectomy, endolaser and cryocoagulation, as well as silicone oil fill. Finally, a penetrating keratoplasty was performed 6 months after the accident. Thereafter, visual acuity improved to 0.1. The histologic examination of the corneal button showed that the wound healing of the incisions that had remained intact was not completed yet. Epithelial plugs of various size were still filling the somewhat dehiscent wound margins. Fibroblastic activity was detected in the surrounding stroma.

CONCLUSION

Even several years after surgery, blunt traumas represent a definite risk for eyes undergoing radial keratotomy.

Multirecurrence of corneal posterior polymorphous dystrophy. An ultrastructural study

Posterior polymorphous corneal dystrophy (PPD) is a rare bilateral, autosomal-dominant disease. The presence of the epitheliumlike endothelium and the thickening of Descemet's membrane by the posterior collagenous layer (PCL) has been reported in the majority of published cases. Reepithelialization of the posterior cornea in donor tissue has been reported only once. Therefore, to examine this process we examined, by light and electron microscopy, three corneal buttons (an original and two subsequent keratoplasties after 3 and 4 years, respectively) from the left eye of a patient with bilateral disease. Our study showed a repopulation of the posterior surface of the donor corneas by the host epitheliumlike endothelium, which was of identical morphology in each case. In contrast to the previously published work, a posterior collagenous layer in the failed grafts was absent from the axial cornea, where the epitheliumlike endothelium was in direct contact with donor Descemet's membrane. A PCL at the periphery in the failed transplants was of the fibrocellular type and differed from the fibrillar PCL in the first keratoplasty specimen. The fibroblastlike cells within the fibrocellular PCL were distinct from the underlying epithelial-like cells and contained numerous tertiary phagolysosomes. We suggest that the major contributor to the fibrocellular PCL in the repeat keratoplasties was a fibrous ingrowth from the host/graft junction and not the epitheliumlike endothelium. It appears that the synthetic capacity of the epitheliumlike endothelium was similar to that of the normal epithelium and was much lower than that of normal native endothelium.

An ultrastructural investigation of an early manifestation of the posterior polymorphous dystrophy of the cornea

BACKGROUND

Posterior polymorphous dystrophy of the cornea is an uncommon, but well-recognized, congenital disease affecting Descemet's membrane and endothelium. Visual impairment usually is minimal and slowly progressive. Edema develops in a small number of patients, necessitating a corneal graft in middle age. An early manifestation of posterior polymorphous dystrophy with corneal edema present at birth or soon thereafter is extremely rare; only a few ultrastructural reports are available.

METHODS

The corneal button of a 5-month-old baby with posterior polymorphous dystrophy was examined by conventional light and electron microscopy.

FINDINGS

The anterior banded zone of Descemet's membrane was thinned (2 microns) in the axial part of the cornea, contained defects in the paraxial part, and was absent at the periphery. Where present, the anterior banded zone was lined posteriorly by a fibrocellular layer (containing fibroblast-like spindle cells and striated collagen fibrils) and a fibrillar layer forming an abnormal posterior collagenous layer. This layer was lined posteriorly by degenerate overlapping endothelial cells, which also were in apposition to the stroma in regions with an absent anterior banded zone. The defects in Descemet's membrane were used by the abnormal keratocytes to migrate between the anterior banded zone and the posterior collagenous layer. At the periphery, a multilayer of spindle cells was present behind the stroma.

CONCLUSIONS

Failure to produce a continuous anterior banded zone indicates an onset of the disease before the twelfth week of gestation. It appears that, in posterior polymorphous dystrophy, there is a mosaic of better preserved and dystrophic endothelial cells and that the presence or absence of the normal components of Descemet's membrane is determined by the proportion of dystrophic cells in the endothelial cell population.

Bilateral uveal melanoma presenting simultaneously

A case of bilateral uveal melanoma in a 54-year-old man is described. On admission of the patient for a choroidal melanoma of the left eye, an asymptomatic ciliary-body tumour was detected in his right eye. A thorough general examination did not reveal any metastases. The left eye was enucleated and local excision of the tumour in the right eye was performed 2 months later. Histology confirmed the presence of malignant melanomas in both eyes. The tumours were of similar A/B spindle-cell type. The patient remained healthy, showing no sign of metastasis or local recurrence of melanoma 9 months after the date of diagnosis. The visual acuity in his remaining eye remained 6/6. Immunological assessment of the blood serum revealed abnormally high interleukin 1 beta (IL-1 beta) and IL-2 levels. Possible implications of these findings are discussed.

Immuno-electron labelling of matrix components in congenital hereditary endothelial dystrophy

Two corneal buttons were obtained from a patient with congenital hereditary endothelial dystrophy (CHED) at the ages of 2.5 years (right eye) and 14 years (left eye) and were studied by light and electron microscopy including immunogold labelling for collagen types I-V and laminin. The posterior collagenous layer (PCL) of Descemet's membrane contained collagen types I, III-V, and laminin: the latter was also localised to fine-banded and granular material in the posterior non-banded zone (PNBZ). Comparison of the endothelium 2.5 years and 14 years revealed occasional dystrophic changes in the former and extensive dystrophic changes in the latter. The distribution of collagen types I, III and V within the PCL supports previous morphological observations of fibroblast-like change of the endothelium in CHED. Persisting endothelial properties were manifest as positive labelling of type IV collagen and laminin. An excessive amount of laminin found in PNBZ and PCL is another stress-related endothelial reaction.