Fiona Roberts

Demodex blepharitis mimicking eyelid sebaceous gland carcinoma

prudent to consider both tobacco and alcohol as risk factors to be avoided in carriers of LHON. Pfeiffer et al. recently described five older (>60) patients with LHON who lost vision. They were all male. Dr Grzybowski asks, reasonably, why, if estrogen (partially) protects women before menopause, there is a gender bias after 60. We, like the authors, do not know. Five is a small number, some women take hormonal replacement therapy, and some women maintain estrogen levels after menopause that are still higher than those of men. We agree with Dr. Grzybowski that Osborne et al. have an interesting hypothesis regarding the effects of light on retinal ganglion cells (RGCs) and their axons. They propose that given low ATP levels from genetically impaired mitochondria, reactive oxygen species may induce RGCs to die. However, these and other interesting considerations pertaining to the pathophysiology of LHON were well beyond the scope of our article, which represented a personal tale and related a series of studies that went from bench to bedside and back to the bench in rewarding cycles.

Educational report: A case of lacrimal sac rhinosporidiosis

ABSTRACT This article reports a presentation of lacrimal sac rhinosporidiosis and informs the reader of this uncommon but important diagnosis. A 36-year-old man from Pakistan presented with a 3-month history of swelling at the nasal aspect of the left lower lid. This was associated with occasional crepitus and slight localised discomfort, but no epiphora. There was a palpable fullness near the left medial canthus associated with telecanthus but a normal sac washout and normal eye examination otherwise. Previous medical history included an ipsilateral nasal polypectomy and inferior meatal antrostomy around 10 years previously, whilst living in Pakistan. Various imaging modalities were useful in identifying a soft tissue mass within the left nasolacrimal duct. Following excision biopsy, histological examination confirmed the presence of rhinosporidiosis, likely caused by the organism Rhinosporidium seeberi. Rhinosporidiosis should be considered as a potential cause in any case of lacrimal sac pathology. Imaging studies may be helpful in measuring the extent of disease, although histological examination is required to confirm the diagnosis. Although rare, the complications of rhinosporidiosis can be potentially blinding or fatal. As discussed in this case, the presence of telecanthus may represent a lacrimal system tumour, either malignant or benign, and should always prompt further investigation.

Treatment of Retinal Detachment

This chapter serves primarily as a guide to the causative pathology and the secondary disturbances that are encountered when an enucleated eye is submitted with a clinical history of “Retinal detachment – treatment unsuccessful.” Retinal detachment may be “Rhegmatogenous” which occurs when fluid passes from the vitreous cavity through a hole in the retina into the “subretinal space.” The “hole” or “tear” is most commonly secondary to degenerative disease in the retina and vitreous. By contrast, “exudative” detachment refers to accumulation of fluid under the neural retina in situations in which there is abnormally excessive permeability in the retinal vessels or in the choroidal vessels. This process is encountered in inflammation or neoplasia and in retinal or choroidal vasculopathy with loss of endothelial cell integrity, and in this event the subretinal space is filled with a more viscous proteinaceous exudate. “Traction” detachment occurs when there is condensation or organization of the vitreous, by trauma or neovascularization. In the treatment of retinal detachment there are basically two lines of approach to sealing off a hole in the retina after subretinal fluid has been drained either by indenting the sclera and choroid so that the retinal hole is sealed or by replacing the vitreous with a bubble of silicone oil, or inert gas. The pathological effects at these attempts at treatment are commonly seen in globes enucleated for retinal detachment.

Biopsy of the Eyelid, the Lacrimal Sac, and the Temporal Artery

This chapter is not intended to be a comprehensive account of diseases of the skin and soft tissue, for which subjects excellent textbooks are widely available. The topics chosen are those commonly encountered in an ophthalmic pathology laboratory. The most common malignant eyelid specimens are basal cell carcinomas with far fewer squamous and sebaceous carcinomas. Benign pathology includes papillomas (basal or squamous cell, chalazia and naevi. Solar keratosis, lymphoma, angiomas and adnexal tumours are less common. Melanoma is rare. In many conditions there can be poor correlation between clinical and histological diagnosis emphasizing the need for a tissue diagnosis in all excised specimens.

Examination of the Globe. Technical Aspects

This chapter emphasises the methodology that is standard practice in the specialist ophthalmic pathology laboratory, but it also includes descriptions of the techniques that are recommended for investigation at the level necessary for presentation or publication. There is a description of techniques for handling the globe, the common macroscopic changes and normal histology. Information on special stains, immunohistochemistry and additional ancillary techniques is included but more detailed accounts are available in other pathology texts. The information included in this chapter should be underpinned by detailed background knowledge of clinical ophthalmology.

The Malformed Eye

Malformations of the eye, orbit, and adnexa are encountered in three forms. The most common are of a relatively minor nature such as colobomata of the uveal tract and minor malformations of the retina and optic nerve head and do not require treatment. The next group are amenable to surgical intervention and excised tissue may be submitted to the laboratory for investigation. Lastly, there are those in which major or minor degrees of ocular malformation are associated with severe and often lethal systemic disorders (e.g., synophthalmia, anencephaly, and gross chromosomal abnormalities such as the trisomy D group); these abnormalities may be encountered at autopsy. To understand these developmental anomalies an understanding of normal development is required.

Retinal Vascular Disease

Ischaemic retinal vascular diseases ultimately lead to glaucoma and are found in the globes that are enucleated to relieve intractable pain in a blind eye. The clinical diagnosis is usually “neovascular glaucoma” with the addition of “central retinal vein occlusion” or “diabetes,” but occasionally, rarer entities such as retinopathy of prematurity or Coats’ disease will be seen at this end stage. Angiogenic factors released by the ischaemic retina are important in the pathogenesis of these retinal vascular diseases. Central retinal artery occlusion, posterior ciliary artery occlusion, ophthalmic artery occlusion, hypertension and disseminated intravascular coagulation are rarely associated with neovascular glaucoma. Choroidal neovascularisation (disciform degeneration) and age related macular degeneration are included in this chapter although they do not per se lead to anterior segment neovascularisation.

The Orbit: Biopsy, Excision Biopsy, and Exenteration Specimens

Imaging advances has improved the preoperative assessment of space-occupying masses in the orbit but biopsy is still important in the definitive diagnosis of an orbital mass. Most orbital problems cause proptosis or disorders of ocular motility. In adults the commonest pathology includes vascular tumours, lymphoma, chronic idiopathic orbital inflammatory disease and tumours of the periorbital and lacrimal gland. Tumours of the bone and soft tissues are relatively rare. The most common tumours of the lacrimal gland are pleomorphic adenoma and adenoid cystic carcinoma. In children benign cysts, including dermoid cysts, vascular tumours, sarcomas and tumours of the optic nerve predominate. Rhabdomyosarcoma is the most common primary sarcoma of the orbit and can form a rapidly expanding mass in children. Optic nerve tumours are associated with neurofibromatosis type 1. They are termed optic nerve glioma but show identical morphology to pilocytic astrocytomas.

The Corneal Disc

Corneal transplantation is one of the most successful forms of homograft. This can be undertaken for a variety of diseases that cause corneal opacification, vascularisation, scarring and ulceration. Keratoplasty has transformed in recent years and although penetrating keratoplasty is still performed on a wide range of conditions techniques such as deep anterior lamellar keratoplasty for anterior pathology and Descemet’s membrane stripping with endothelial keratoplasty for posterior problems is now commonplace. The most common cause for keratoplasty used to be bullous keratopathy related to endothelial cell deficiency caused by anterior chamber lens implants. This has now decreased incidence and keratoconus is more common. There are also a host of infectious agents which cause keratitis including bacteria, fungi and parasites. Corneal dystrophies are uncommon but of pathological interest and can affect the anterior cornea and Bowman’s layer, the stroma and the endothelium. A significant number of specimens will result from repeat keratoplasty and the potential findings in these specimens include inflammation in relation to the host graft junction and endothelium, a retrocorneal fibrous membrane or simply loss of endothelial cells. The cornea may also be subject to mechanical trauma, burns and damage by heat and irradiation.

“Autopsy Eye” – The Eye in Systemic Disease

Autopsy is often the only way of obtaining material for histological study from conditions such as age-related macular degeneration or various retinopathies. It is also a valuable source that allows the study of the eye in various systemic or multisystem diseases. If systemic hypertension is uncontrolled this leads to retinal vascular ischaemia usually by way of microinfarcts. Fibrinoid necrosis may be seen in choroidal vessels. Sclerokeratitis may be seen in rheumatoid arthritis, various vasculitides and other autoimmune diseases such as systemic lupus erythematosus. Deposits of leukaemia and lymphoma are usually seen in the choroid and haemorrhages may also occur. Retinitis pigmentosa is frequently only studied at the late stage where there is bone spicule pigmentation with sparing of the macular region. A common feature in syndromic retinal degeneration appears to be abnormalities in the cilia. Metabolic deficiencies may also affect the eye. These include lysosomal storage disorders, peroxisomal storage disorders, lipofuscinosis and aminoacidopathies. Mitochondrial disorders also occur. The effects of demyelinating disease such as multiple sclerosis may also be seen in the eye.