Pathology of the Head and Neck

Eye and Ocular Adnexa Chapter 10 301From the glial tumours, only astrocytomas can be foundin the retina and optic nerve. Optic pathway gliomas arefrequently asymptomatic; sometimes they demonstraterapid growth, causing considerable visual dysfunction,neurologic deficits, and endocrine disturbances. Mostoptic pathway gliomas are diagnosed in patients withneurofibromatosis. Children with optic pathway gliomasassociated with neurofibromatosis 1 predominantlyhave multifocal lesions.Benign astrocytic tumours of the retina ( astrocytichamartomas) most frequently occur in patients with tuberoussclerosis. Retinal astrocytic hamartoma and retinoblastomamay be very similar clinically and their differentiationin atypical cases can be difficult, even withthe use of ultrasonography and computed tomography.Histologically, a well-circumscribed glial cell proliferation,sparing the outer layers of the retina will be visible.10.4.5.5 Vascular10.4.5.5.1 Angiomatosis RetinaeFig. 10.25. Retinoblastoma: detail of the small blue round cellswith high mitotic and apoptotic activitynodular thickening of the retina). The diffuse growthpattern has a bad prognosis. Trans-scleral spread of retinoblastomais uncommon. The tumour usually spreadsinto the meninges or parenchyma of the optic nerve. Forthis reason, it is important to take transverse blocks ofthe cut surface of the optic nerve, before cutting the enucleatedeye. Microscopic examination will show a smallblue round cell tumour with a high mitotic rate. Thecells have ill-defined cytoplasm and inconspicuous nucleoli.Rosettes are frequently seen and apoptosis is common(Figs. 10.24, 10.25). Glial differentiation is rare. Ifthe tumour was irradiated before enucleation, amorphouscalcified structures will be present. Immunohistochemistryof retinoblastomas will show positivity forS-100, GFAP and NSE. Use of these markers can be helpfulnot only in identifying the tumour, but also in identifyingthe spread of the tumour. Choroidal invasion inparticular can be hard to recognise in an H&E staining.Axonal degeneration in the optic nerve, with reactiveproliferation of astrocytes has to be differentiated fromreal tumour spread.Von Hippel-Lindau disease is an autosomal dominantlyinherited multi-system disorder characterised by haemangioblasticlesions of the central nervous system andvisceral organs [126]. Angiomatosis retinae (retinal haemangioblastoma)is often the first observable manifestationof von Hippel-Lindau disease. Histology showsa proliferation of capillary endothelial cells and vacuolatedstromal cells.In some patients with von Hippel-Lindau disease orin the close relatives of such patients, unusual retinalvascular hamartomas other than retinal angiomas canbe detected.10.4.5.5.2 Cavernousand Capillary HaemangiomaICD-O:9120/0Haemangiomas of the choroid can be diagnosed clinicallyby fluorescein angiography. Diffuse haemangiomatosiswith facial skin involvement can be seen in theSturge-Weber syndrome. The treatment of these vascularlesions is radiation (external beam or radioactiveplaque); for this reason pathologists do not see theselesions very often. Only when the haemangiomas leadto retinal attachment and blindness will enucleation follow.The excised globe usually shows reactive changesdue to radiotherapy.10.4.5.4 Glial10.4.5.6 Other Primary TumoursTumours other than melanocytic, lymphoid, retinoblasticand vascular can be found in the intraocular structures,but they are extremely rare. In the iris leiomyoma,leiomyosarcoma, schwannoma, juvenile xanthogranuloma,rhabdomyosarcoma, inclusion cysts of the pigmentepithelium, primary adenoma of the iris pigmentepithelium and adenocarcinoma have been reported.In the ciliary body leiomyomas, leiomyosarcomas,schwannomas, adenomas and medulloepitheliomas can befound, and in the choroid osteomas, adenomas and adenocarcinomasof the retinal pigment epithelium and hamar-