Pathology of the Head and Neck

Eye and Ocular Adnexa Chapter 10 295retinitis can also be visualised with DNA in situ hybridisation.10.4.2.2 Chronic Non-GranulomatousInflammationChronic non-granulomatous inflammation of the uvealtract is a poorly understood condition. It can be dividedinto anterior uveitis, with risk of secondary angle closureglaucoma, and posterior uveitis with risk of degenerationof retinal pigment epithelium. The histology isnon-specific, with only a few lymphocytes in the uvealtissues.Fig. 10.17. Cytomegaloviral retinitis: large eosinophilic inclusionsare present in the infected endothelial cells. In this biopsythe retina showed almost no signs of necrosis, which is uncommonin cytomegalovirus retinitisdisciform keratitis, retinopathy, microphthalmus oropen-angle glaucoma [3, 51]. In societies with immunisationthe condition is rare. The histologic findings inthe lens are characteristic, but it should be mentionedthat the features may not yet be apparent in foetal eyesafter early elective termination of pregnancy [38]. Thecentral nucleus of the lens, which is normally free ofcells, shows pyknotic nuclei. There is an abrupt transitionfrom the central nucleus into the normal peripheralcortex of the lens [128].10.4.2 Inflammatory Processes10.4.2.1 Acute InflammationAcute endophthalmitis or panophthalmitis can occuras a postoperative complication or following a trauma[12, 57]. Endocarditis or injection of contaminatedmaterial in drug addicts can be the cause of metastaticbacterial infection, especially in immunocompromisedpatients [89]. Not only bacterial, but also fungal andviral infections can cause acute endophthalmitis. Histologyshows an extensive infiltrate of leukocytes withdestruction of intraocular tissues. The pathogen cansometimes be found in Gram, PAS or Silver stains.Acute necrotising retinitis and low-grade uveitiscan be seen in cytomegaloviral and herpes infection(Fig. 10.17). The characteristic eosinophilic inclusionsof the cytomegalovirus can be found in the cytoplasmand nuclei of infected cells. Immunohistochemicalstaining with anti-cytomegalovirus can be helpful inidentifying the virus. The inclusions of herpes simplex10.4.2.3 Granulomatous InflammationThe specific granulomatous inflammations of the intra-oculartissues can be divided into infectious andautoimmune causes. The autoimmune diseases are sarcoidosis,sympathetic ophthalmitis and lens-induceduveitis. While many of these diseases may be appropriatelytreated with immunosuppressive medication, themanagement of infectious uveitis is antimicrobial therapy.Inappropriate immunosuppressive therapy may bedisastrous for patients with an infection. Chorioretinalbiopsy may provide useful information for determiningthe diagnosis and guiding the subsequent managementof patients with progressive chorioretinal lesions of unknownaetiology [69].10.4.2.3.1 InfectiousThe most important causes of infectious granulomatousinflammatory diseases of the intraocular tissues are tuberculosisand toxoplasmosis.Tuberculosis is rare and shows caseating granulomas,in which tubercle bacilli can be found in a Ziehl-Neelsenstaining.Toxoplasmic retinochoroiditis in neonates infectedin utero with Toxoplasma gondii can show a wide variationin the pattern of tissue destruction. The disease canbe limited to a low grade uveitis and retinal lymphocyticperivasculitis. In more severely affected eyes focal, sectorialor total retinal destruction can be seen. Toxoplasmacysts can be found in the retina and optic nerve. Inthe most severely affected eyes the retina is necrotic andcalcified [5].10.4.2.3.2 SarcoidosisIn patients with systemic sarcoidosis, ocular involvementcan occur. Most frequently affected are the retina, the