Eye cancer develops in the eye and is a rare disease. The diagnosis is difficult and is usually made during a routine eye examination. Several eye cancer types exist, depending on the structure and the cells involved. The stages of eye tumors range from stage 1 to stage 4.
The eye is a complex organ comprising tissues with significant structural and functional variations. These structures include the conjunctiva, retina, choroid, ciliary body, iris, and lacrimal gland. When the cells of one or more of these structures undergo mutation and start dividing and proliferating uncontrollably, the condition is known as eye cancer. An eye tumor is both life-threatening and vision-threatening and has the potential to metastasize to other organs.
Eye cancer is a rare disease. Most cases of eye cancer are secondary, i.e., the cancer starts in other parts of the body and spreads to the eyes (metastasis). In the United States, the estimated prevalence rate is about 12/100,000 people, while the incidence rate is about 1/100,000 people. In India, the incidence rate of eye tumors among all cancers is about <0.5%. Studies have reported a higher burden of eye tumors in India, and the cases are increasing. The increasing trend may partially be due to better cancer detection techniques, epidemiological transition, and more effective cancer data collection.
Depending on the type of cell it originates from, eye cancer is classified into different types. The following are the different types of eye cancer:
It is one of the most common primary eye cancer types and affects the uvea. The condition may develop in the choroid, ciliary body, or iris. The condition is also subdivided into classes 1 (having low metastatic risk) and 2 (having high metastatic risk). Patients with uveal melanoma have higher metastatic disease-related mortality and visual morbidity.
This condition occurs in the iris and constitutes about 5% of all uveal melanomas. Most iris melanoma cases are asymptomatic and generally diagnosed during routine eye examinations.
It is a rare subtype of uveal melanoma and generally occurs with iris and choroidal melanoma. The condition may present without symptoms for a considerable period and is generally diagnosed in advanced stages.
It is one of the most common primary intraocular cancers. It is the second most common location for developing melanoma. The condition is diagnosed through various techniques, such as indirect ophthalmoscopy, fundus fluorescein angiography, A- and B-ultrasonography scans, and transillumination.
Intraocular lymphoma is an ocular cancer generally considered a part of central nervous system lymphoma. The disease includes primary and secondary intraocular lymphoma. The condition may develop in the optic nerve, Bruch's membrane, vitreous, uvea, and retina. Intraocular lymphoma primarily arises from the B-cell; however, some intraocular lymphoma may also arise from T-cells. Intraocular cancers are tumors inside the eye.
Orbital tumors are benign or malignant lesions that develop in the tissues surrounding the eyes. They may be primary or secondary. This type of eye tumor may be characterized by vascular lesions, cysts, neurogenic tumors, lymphomas, and secondary tumors. Eyelid tumors develop in the eyelid.
It is the most common type of eyelid cancer (90%) and usually develops in the lower eyelid. The risk factors include a history of ionizing radiation exposure, systemic and local immune dysfunction, and ultraviolet radiation.
Squamous cell carcinoma of the eyelid constitutes about 5% of all eyelid tumors. Risk factors for this condition include chronic skin lesions, albinism, and genetic skin disorders, such as epidermodysplasia verruciformis and xeroderma pigmentosum.
The condition commonly affects children and is characterized by the presence of tumor lesions around the eye. Almost 90% of cases of orbital rhabdomyosarcoma occur before the age of 16, and the mean age of onset is around 5 to 7 years.
Conjunctival tumors occur in the conjunctiva and are divided into carcinoma in situ, dysplasia, and squamous cell carcinoma. The risk factors for these tumors include immunodeficiency, human papillomavirus (HPV), and exposure to ultraviolet radiation.
Lacrimal gland tumors occur in the lacrimal glands of the eye and constitute about 10% of all orbital tumors. Lacrimal gland tumors are of different types, such as epithelial tumors and lacrimal gland lymphomas.
It is one of the most common cancers in childhood and constitutes about 3% of all childhood malignancies. The condition is characterized by strabismus, leukocoria, red eyes, pain, and reduced vision.
Basal cell carcinoma may occur in various parts of the eye, including the conjunctiva. However, BCC in conjunctiva is rare.
Conjunctival squamous cell carcinoma is a subset of ocular surface squamous neoplasia (OSSN). The disease is characterized by vision loss. The advanced stage of the disease may cause death.
Different stages of intraocular melanoma involving the iris are:
The lesion is limited only to the iris and is less than one-fourth of the size of the iris.
It is limited to the iris and greater than one-fourth of the iris size, OR is limited to the iris and results in glaucoma, OR extends to the ciliary body.
The tumor extends into the choroid and does not cause glaucoma, OR the tumor grows into the choroid, ciliary body, or both with or without involving the sclera.
The tumor extends into the choroid and causes glaucoma, OR the tumor extends out of the sclera, but its size is limited to less than 5 mm in diameter.
The tumor extends out of the sclera with a diameter greater than 5 mm.
Cancer grows into the surrounding lymph nodes or distant organs, including the liver, lungs, or bone.
Cancer of the eye occurs in any part of the eye. There are multiple eye cancer types. The most common eye cancer types include uveal melanoma, conjunctival cancer, eyelid cancer, and rhabdomyosarcoma. While stage 1 is the early stage or first stage of eye cancer, stage 4 is the last stage of eye cancer.