Intraocular Tumors
A variety of tumors can cause unilateral glaucoma. Many of the tumors described in this section are also discussed in BCSC Section 4, Ophthalmic Pathology and Intraocular Tumors. Depending on the size, type, and location of the tumor, IOP elevation can result from several different mechanisms, including
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direct tumor invasion of the anterior chamber angle
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angle closure resulting from rotation of the ciliary body or from anterior displacement of the lens–iris interface (see Chapter 10)
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intraocular hemorrhage
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neovascularization of the angle
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deposition of tumor cells, inflammatory cells, and cellular debris within the trabecular meshwork
Choroidal and retinal tumors typically cause a secondary angle-closure glaucoma by the anterior displacement of the lens–iris diaphragm, which results in closure of the anterior chamber angle. Posterior synechiae may develop as a result of inflammation of necrotic tumors; they exacerbate angle closure through a pupillary block mechanism. Choroidal melanomas, medulloepitheliomas, and retinoblastomas may also cause neovascularization of the angle, which can result in angle closure. Neovascularization of the angle may also occur after radiation therapy for intraocular tumors.
The most common cause of IOP elevation associated with primary or metastatic tumors of the ciliary body is direct invasion of the anterior chamber angle. This can be exacerbated by anterior segment hemorrhage and inflammation, which further obstruct aqueous outflow. Necrotic tumor and tumor-laden macrophages may cause obstruction of the trabecular meshwork and result in a secondary OAG. Tumors causing a secondary glaucoma in adults include uveal melanoma and melanocytoma (Figs 8-11, 8-12), metastatic carcinoma, lymphoma, and leukemia. In children, tumors associated with glaucoma include retinoblastoma, juvenile xanthogranuloma, and medulloepithelioma.
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Camp DA, Yadav P, Dalvin LA, Shields CL. Glaucoma secondary to intraocular tumors: mechanisms and management. Curr Opin Ophthalmol. 2019;30(2):71–81.
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Shields CL, Materin MA, Shields JA, Gershenbaum E, Singh AD, Smith A. Factors associated with elevated intraocular pressure in eyes with iris melanoma. Br J Ophthalmol. 2001;85(6):666–669.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.