Severe ulcerative keratopathy following implantation of an acellular porcine corneal stromal lenticule in a patient with keratoconus

PURPOSE

To report a case of ulcerative keratopathy following implantation of acellular porcine corneal stroma (APCS) in a patient with keratoconus (KC).

METHODS

A 58 year-old patient initially presented with an ulcerative keratopathy in the left eye. Previously, several corneal procedures (including radial keratotomy, laser-in-situ keratomileusis, crosslinking) were performed for KC. Eight months ago, an APCS lenticule (Xenia corneal implant, Gebauer Medizintechnik GmbH, Neuhausen, Germany) was implanted into a stromal pocket because of progressive keratectasia. Visual acuity was hand movement. Anterior segment optical coherence tomography showed a space between the APCS lenticule and the host stroma. Excimer laser-assisted penetrating keratoplasty (PKP, 8.0/8.1 mm) was performed in the left eye. The corneal explant was investigated by light and transmission electron microscopy.

RESULTS

Best-corrected visual acuity was 20/40 six weeks after PKP. Light microscopy demonstrated a stromal ulceration down to the APCS lenticule. No stromal cells could be found within the APCS lenticule eight months after implantation. The APCS lenticule did not show a green stain of the collagens with Masson-Goldner staining and exhibited a strong Periodic acid-Schiff positive reaction. Electron microscopy of the APCS lenticule revealed cross-linked collagen lamellae without cellular components. Close to the interface, corneal collagen lamellae of the host cornea were disorganized. Few vital keratocytes were present on the surface of the lenticule and appeared to cause mechanical disruption of the host stroma along the lenticule-stroma interface.

CONCLUSION

APCS implantation may lead to severe complications such as ulcerative keratopathy in otherwise uncomplicated KC corneas. In such cases, excimer laser-assisted PKP or Deep Anterior Lamellar Keratoplasty are the methods of choice to restore visual acuity.

Long-Term Follow-Up of Pediatric Excimer Laser-Assisted Penetrating Keratoplasty for Congenital Stromal Corneal Dystrophy

PURPOSE

The purpose of this study was to highlight characteristic clinical and microscopic findings and report the long-term follow-up of pediatric excimer laser-assisted penetrating keratoplasty (excimer-PKP) for congenital stromal corneal dystrophy (CSCD).

METHODS

A 2-year-old Greek child presented with CSCD at our department. Clinical examination showed bilateral flake-like whitish corneal opacities affecting the entire corneal stroma up to the limbus. Genetic testing identified a mutation of the decorin gene (c.962delA). The variant was not present in the parents and represented a de novo mutation. The uncorrected visual acuity was 20/100 in both eyes. Excimer-PKP (8.0/8.1 mm) was performed on the right eye at the age of 2.5 years and on the left eye at the age of 3 years. Postoperatively, alternating occlusion treatment was performed.

RESULTS

The light microscopic examination demonstrated a disorganized extracellular matrix of the corneal stroma characterized by a prominent irregular arrangement of stromal collagen lamellae with large interlamellar clefts containing ground substance, highlighted by periodic acid-Schiff- and Alcian blue-positive reaction detecting acid mucopolysaccharides. Electron microscopy showed disorganization and caliber variation of collagen lamellae and thin filaments within an electron-lucent ground substance. The postoperative course was unremarkable. Both grafts remained completely clear 14 years postoperatively. Corneal tomography showed moderate regular astigmatism with normal corneal thickness. The corrected distance visual acuity was 20/25 in both eyes.

CONCLUSIONS

Excimer-PKP for CSCD might be associated with excellent long-term results and a good prognosis, particularly when the primary surgery is performed at a very young age. However, this requires close postoperative follow-up examinations by an experienced pediatric ophthalmologist to avoid severe amblyopia.

Recurrent Filamentous Fungal Keratitis Caused When the Primarily Selected Graft Diameter was Too Small

PURPOSE

To establish the importance of using a sufficiently large corneal graft in primary penetrating keratoplasty in order to prevent recurrence of fungal keratitis.

OBERSERVATIONS

A 58-year-old female patient underwent emergency penetrating keratoplasty (diameter 7.0 mm, double running suture) for therapy-resistant fungal keratitis (Fusarium solani) at an external eye clinic. Despite intensive antifungal therapy, new fungal infiltrates appeared in the host cornea after a few days. The patient was referred to our department for further treatment. On first presentation, circular infiltrates were seen around the corneal graft with anterior chamber involvement and therapy-resistant hypopyon. We performed an emergency penetrating repeat keratoplasty (diameter of 13.0 mm, 32 interrupted sutures) combined with anterior chamber lavage and intracameral and intrastromal drug injection.

CONCLUSION AND IMPORTANCE

Fungal keratitis sometimes has a frustrating clinical course. Therefore, early diagnosis with effective therapy initiation is of the utmost importance. In cases of penetrating keratoplasty, optimal planning and timing (before anterior chamber involvement) should be provided. Sufficient safety distance must be ensured in the choice of graft diameter, fixation with multiple interrupted sutures, and anterior chamber lavage, as well as intracameral and intrastromal drug administration. Incomplete excision carries a risk of recurrence and endophthalmitis in the course. Close postoperative control is necessary to detect early recurrences.

Ultrastructural Examination of the Corneal Interface after Predescemetic Deep Anterior Lamellar Keratoplasty (DALK) - A Case Report with Light and Transmission Electron Microscopy

PURPOSE

To examine corneal buttons with light and transmission electron microscopy (TEM) to visualize the interface area and highlight the ultrastructural corneal changes after deep anterior lamellar keratoplasty (DALK).

METHODS

Two patients underwent excimer laser-assisted penetrating repeat keratoplasty after predescemetic DALK. The corneal buttons were examined by light microscopy and TEM.

RESULTS

The light microscopic examination of the corneal buttons revealed fragments of a second Descemet's membrane in the central and midperipheral areas (Case 1). In both cases, visualization of the interface area was not possible by light microscopy. The donor and host stroma were tightly attached without dehiscence. TEM identified the interface area by irregularities in the collagen distribution between the donor and host stroma. The thickness of the remaining recipient corneal stroma measured approximately 30 µm (Case 1) and 100 µm (Case 2), respectively. In the host stroma, TEM revealed the absence or degeneration of keratocytes, accumulation of amorphous material between the collagen lamellae, and vacuolar inclusions dispersed in the stroma, forming a band-like zone anterior to Descemet's membrane.

CONCLUSION

The interface area after DALK has been mainly investigated by in vivo confocal microscopy. Light microscopy and TEM findings indicate remodeling processes after DALK that are associated with increased keratocyte degeneration and structural alterations of the extracellular matrix in the host stroma. The choice of surgical method may influence the postoperative morphological and functional outcome since these findings were primarily apparent in the remaining host stroma. Therefore, complete exposure of Descemet's membrane is an important prognostic factor for the postoperative visual outcome.

Corneal Perforation as a Rare and Late Manifestation of Choroidal Melanoma

PURPOSE

To report a case of corneal perforation as a rare and late manifestation of choroidal melanoma and to highlight the major histopathological findings of this unusual combined clinical presentation.

METHODS

A 74-year-old male patient presented to our department due to corneal perforation of the right eye with the absence of light perception for 6 months. The intraocular pressure was hard on palpation. Because of the protracted finding and reduced visual prognosis, primary enucleation was performed.

RESULTS

The histopathological examination revealed choroidal melanoma with epithelioid and spindle cell components at the posterior pole, which was positive for Melan-A, Human Melanoma Black 45 (HMB45), BAP1, and SOX10. The anterior segment showed complete anterior chamber hemorrhage and blood remnants in the trabecular meshwork. The cornea displayed diffuse blood staining with hemosiderin and hemosiderin-loaded macrophages and keratocytes. No inflammatory cells were present near the corneal perforation, which had a width of 3 mm. Intraocular heterotopic ossification was indicative of a long-standing condition. Postoperative cancer staging was normal.

CONCLUSION

Corneal perforation should be considered as a very rare and late manifestation of advanced choroidal melanoma and may result from interaction between intraocular hemorrhage, elevated IOP, and its secondary signs such as corneal blood staining.

[Recurrence risk of periocular basal cell carcinoma after histologically controlled excision]

BACKGROUND AND OBJECTIVE

The incidence of basal cell carcinoma (BCC) has significantly increased in the last decades. The aim of this retrospective study was to determine the risk of recurrence of periocular BCC after histologically controlled resection.

PATIENTS AND METHODS

Based on the clinical records from 2009-2020 a total of 270 consecutive periocular BCCs from 243 patients were investigated with respect to recurrence after surgical excision. For this study, the type of BCC (primary or recurrent BCC) and localization within the orbital region (upper eyelid nasal, middle, temporal and lower eyelid nasal, middle, temporal) and the histological BCC subtype, e.g. solid/nodular (s/n), superficial multicentric (s-m), infiltrative/sclerodermal (i/s), basosquamous (bsq) and mixed (gem), were recorded. Recurrence rates were compared using χ²-tests.

RESULTS

The 270 resected BCCs with 231 primary BCC (pBCC) and 39 already recurrent BCC (rBCC), were included in this study. Among the 231 pBCCs we recorded a total of 38 (16.5%, 2‑year recurrence rate 9.2%) recurrences for the abovementioned period. In the 39 rBCCs we observed 18 (46.2%) recurrences (2-year recurrence rate 37.8%). In addition, a significantly shorter recurrence-free interval (RFV, ∅ 52.6 ± 9.0 months) was observed for the rBCC than for the pBCC (∅108.6 ± 4.1 months, p < 0.001). The recurrence rates did not differ significantly with respect to the location; however, there was a significant difference between the five defined subtypes (p = 0.001): s/n = 15.9%, s‑m = 45.0%, i/s = 27.8%, bsq = 33.3% and gem = 40.0%. After R0 resection the recurrence rate of s/n BCC was significantly lower than after R?/R1 resection (p = 0.008). The histological subtypes i/s (p = 0.433), bsq (p = 0.417), and gem (p = 0.143), showed no significant difference between the recurrence rates after R0 and R?/R1 resection. In s‑m BCC, a conclusion on the statistical significance was not possible.

DISCUSSION

The recurrence rate appears to be comparatively high; however, R1 resected BCCs were intentionally included in this study to obtain an evaluation that reflects clinical practice as realistically as possible. It is possible that the surgical procedure and/or the type of histological examination as well as the broad interpretation of the term local recurrence could be the reason for the different recurrence data in the literature. Our data indicate that the recurrence rate is not affected by the exact localization within the orbital region, but by the respective BCC subtype. As recurrences may develop years after BCC excision a long-term follow-up is strictly recommended.

Infectious Crystalline Keratopathy after Penetrating Keratoplasty with Light and Electron Microscopic Examination

PURPOSE

To highlight the typical histological and ultrastructural features of severe infectious crystalline keratopathy (ICK) in a corneal graft, which required excimer laser-assisted repeat penetrating keratoplasty (PKP) and to present the challenging treatment conditions associated with ICK.

METHODS

An 85-year-old female patient underwent PKP for secondary graft failure after Descemet membrane endothelial keratoplasty (DMEK) for Fuchs' endothelial corneal dystrophy in the left eye. One year later, white branched opacities were observed in the superficial corneal stroma of the graft without surrounding inflammation in the left eye. The patient underwent excimer laser-assisted repeat PKP (8.0/8.1 mm) in the left eye after prolonged refractory topical anti-infectious treatment for 1 month. The corneal explant was further examined by light and transmission electron microscopy (TEM).

RESULTS

The light microscopic examination of the corneal explant demonstrated aggregates of coccoid bacteria in the superficial and mid-stromal region that were positive for periodic acid-Schiff (PAS) and Gram stain. The bacterial aggregates extended into the interlamellar spaces, showed a spindle-shaped appearance, and were not surrounded by an inflammatory cellular reaction. TEM demonstrated lamellae separation within the anterior corneal stroma with spindle-shaped aggregates of bacteria, which were embedded in an extracellular amorphous matrix with incipient calcification, being consistent with a biofilm. No inflammatory cellular reaction was evident by TEM. At discharge from hospital, the corrected visual acuity was 20/80 in the left eye.

CONCLUSION

ICK is often challenging due to the difficult diagnosis and treatment conditions. The refractory courses are mainly attributed to a biofilm formation, which inhibits effective topical anti-infectious treatment. In such cases, (repeat) PKP may be necessary to completely remove the pathology, prevent recurrences, and improve vision.

Descemet Membrane Endothelial Keratoplasty (DMEK) for Severe Verrucous Posterior Polymorphous Corneal Dystrophy with Uncommon Clinical and Ultrastructural Findings

PURPOSE

To report a case of severe verrucous posterior polymorphous corneal dystrophy (PPCD) and cataract, which was treated with Descemet membrane endothelial keratoplasty (DMEK) and simultaneous cataract surgery as a triple procedure (Triple-DMEK).

METHODS

A 62-year-old female patient presented to our department for co-evaluation of advanced PPCD with cataract and progressive light sensitivity in both eyes. The clinical examination demonstrated unusual clinical findings with prominent verrucous lesions on the posterior surface of the cornea without corneal decompensation. We performed a Triple-DMEK in case of simultaneous cataract. The corneal tissue was examined by light and transmission electron microscopy.

RESULTS

Intraoperatively, it was difficult to remove the verrucous structures completely after classical descemetorhexis. Light microscopic examination demonstrated epithelium-like transformation of the corneal endothelium by immunostaining (cytokeratin AE1/3 staining). Transmission electron microscopy revealed thickening of Descemet's membrane (18.5 to 30.0 µm). The anterior banded layer had a normal structure and was slightly thickened (3.5 to 5.5 µm). A normal posterior non-banded layer (PNBL) was observed but thinned (2.5 to 4.0 µm) or missing. It was followed by an altered PNBL with abnormal fibrillary inclusions, which was strongly and variably thickened (11.0 to 24.5 µm). The corneal endothelium was degenerated, partially absent, and epithelial-like altered. The nodular lesions were found to consist of a few degenerated cells that were embedded in an amorphous extracellular matrix interspersed with collagen fibers, which were not arranged in regular lamellae, forming the corneal stroma. The occurrence of pigment granules among the cellular debris suggested that the cells were endothelial cells. The corrected distance visual acuity improved from 20/50 to 20/30 in the right eye (+ 0.00/- 1.75/157°) and from 20/60 to 20/30 in the left eye (+ 0.00/- 1.75/33°), with significant improvement in light sensitivity.

CONCLUSION

The clinical and ultrastructural findings seem to be an unusual variant of the typical characteristic appearance of a PPCD. This case demonstrates that Triple-DMEK is feasible even in very advanced dystrophic changes of the posterior corneal surface, with good morphological and functional results.

TRPC6 is altered in COVID-19 pneumonia

In this Letter to the Editor supportive data were presented to a recent paper published in this journal reporting the involvement of TRP channels in COVID-19 pneumonia and its role for new therapies. Since gene expression of TRP channels was found in human lung tissues the protein was not being reported so far. TRP channels are supposed to be involved in the pulmonary inflammation and its symptoms such as fever, cough and others. Here, TRPC6 was investigated in tissues of normal human lungs and of SARS-Cov-2 infected lungs in a preliminary study. Tissue was obtained post mortem from anatomical body donations during dissections and during pathological dissections (13 normal, 4 COVID-19 pneumoniae) and processed for immunohistochemistry. In normal lungs TRPC6 was found in the ciliated epithelium, in the wall of larger lung vessels and in the alveolar septa. In COVID-19 pneumonia the distribution of TRPC6 was different. Inflammatory lesions, cellular infiltrates, hyaline membranes and fibrosis were labelled intensively as well as dilated capillaries. These observations are from four patients with COVID-19 pneumonia.The observations do not elucidate the molecular mechanisms but support the view that TRPC6 channels are involved in normal physiology of normal human lungs and in COVID-19 pneumonia. TRPC6 might aggravate SARS-2 induced inflammation and could be a target for inhibiting drugs.

Recurrent ligneous conjunctivitis after cataract surgery in a 67-year-old male patient: a case report

Background

Ligneous conjunctivitis is a rare form of chronic pseudomembranous conjunctivitis which usually starts during infancy. We report on an unsual case of recurrent ligneous conjunctivitis after cataract surgery in a 67-year-old male patient.

Methods

The equipment used for the slit-lamp images was a Haag Streit slit lamp BX900 Sn 00,406 with 16 × magnifications. The used batch number of the camera was sn00406 and the software was from the company CCS Pawlowski Merge Eye. There were no filters used. The images were saved with a resolution of 300 DPI. Neither downstream nor averaging was used to enhance the resolution of the image in the case presentation section or the figure legend.

The equipment used for the cross-sectional histologic images was a Zeiss Axioskop 40 microscope with an objective lens Zeiss A-Plan × 20/0.45 (Zoom 6.3 × TV 2/3″″C). The used camera was AxioCam MRc5 and the software was ZEN 3.2. The cross-sectional histologic images were saved with a resolution of 2584 × 1936 Pixels. Neither downstream nor averaging was used to enhance the resolution of the image in the case presentation section or the figure legend.

Case presentation

This is a rare case report of ligneous conjunctivitis in a 67-year-old male patient who presented a recurrent conjunctival granuloma after five excisions following cataract surgery in his left eye. We performed a tumor excision with free conjunctival autograft. The histology showed a fibrin crust including macrophages, granulocytes, lymphocytes, and reactively altered squamous cell nests. These findings were consistent with a ″pseudomembrane in conjunctivitis lignosa″. We administered a topical combination of plasminactivator, heparin, cortisone and cyclosporine.

Conclusion

This treatment with the combination of plasminactivator, heparin, cortisone and cyclosporine has proven to be effective in preventing the recurrence of ligneous conjunctivitis.